What
      about the mark on a person’s forehead caused by sujood?
Question

                When a person prays salah,usaually his forehead gets darker because of sajda and people know that he prays. 

Because of this,this person can feel proud and may be some times he likes people to talk positive about him and say good remarks about him because of 
his prayers. 

Is it O.K. or better in this case for this person to do sajda very lightly and softly or what do you suggest.
Praise be to Allah.The Prophet 
      (peace and blessings of Allaah be upon him) commanded us to do rukoo’
      and sujood perfectly and completely.
 It was reported
      from Anas ibn Maalik (may Allaah be pleased with him) that he heard the
      Prophet  (peace and blessings of Allaah be upon him) said: “Do your
      rukoo’ and sujood perfectly and completely, for by the One in Whose Hand
      is my soul, I can see you behind me when you do rukoo’ and sujood.” (Narrated
      by al-Bukhaari, 6268; Muslim, 425)
 Part of doing
      rukoo’ and sujood properly and correctly is to be at ease in both.
 It was reported
      from Abu Hurayrah that a man entered the mosque and prayed. The Messenger
      of Allaah  (peace and blessings of Allaah be upon him) was sitting in
      a corner of the mosque, and the man came and greeted him with salaam. The
      Prophet  (peace and blessings of Allaah be upon him) answered “Wa
      ‘alayk (and also upon you). Go back and pray, for you have not
      prayed.” So he went back and prayed, then he came and greeted the
      Prophet  (peace and blessings of Allaah be upon him) with salaam, and
      the Prophet  (peace and blessings of Allaah be upon him) answered
      “Wa ‘alayk (and also upon you). Go back and pray, for you have not
      prayed yet.” The third time this happened, the man said, “Teach me, O
      Messenger of Allaah.” He said: “When you stand up to pray, do wudoo’
      properly, then face the qiblah and say ‘Allaahu akbar.’ Then recite
      whatever you can of Qur’aan. Then do rukoo’ until you are at ease in
      rukoo’. Then stand up until you are at ease in standing, then do sujood
      until you are at ease in sujood. Then sit up until you are sitting up
      straight. Do that throughout your prayer.” (Narrated by al-Bukhaari, 724; Muslim, 397).
Not doing rukoo’ and sujood properly and completely is something which
      invalidates one's prayer.
 It was reported
      that Abu Mas’ood al-Ansaari al-Badri said: “The Messenger of Allaah
       (peace and blessings of Allaah be upon him) said: ‘A prayer in
      which a person does not straighten his spine in his rukoo’ and sujood
      does not count.” (Narrated by al-Tirmidhi, 265; he said it is
      hasan saheeh. Also narrated by al-Nasaa’i, 1027; Abu Dawood, 855; Ibn
      Maajah, 870) 
Imaam al-Tirmidhi
      said:
 “Prayer
      should be done in accordance with this, according to the scholars among
      the Companions of the Prophet  (peace and blessings of Allaah be upon
      him) and later scholars, who said that a man should straighten his spine
      when he does rukoo’ and sujood.” 
Al-Shaafa'i, Ahmad
      and Ishaaq said: “A prayer in which a person does not straighten his
      spine in his rukoo’ and sujood does not count, because of the hadeeth of
      the Prophet  (peace and blessings of Allaah be upon him): ‘A prayer
      in which a person does not straighten his spine in his rukoo’ and sujood
      does not count.’” (Sunan
      al-Tirmidhi, 2/52)
 It was reported
      from Abu Waa’il that Hudhayfah saw a man who was not doing rukoo’ and
      sujood perfectly and completely. When he finished praying, Hudhayfah said
      to him, “You have not prayed.” He (the narrator) said: “I think he
      said, ‘If you were to die now, you would die on something other than the
      Sunnah of Muhammad  (peace and blessings of Allaah be upon him).’”
      (Narrated
      by al-Bukhaari, 382).
 According to
      another report (758): it was reported that Zayd ibn Wahb said:
      “Hudhayfah saw a man who was not doing rukoo’ and sujood perfectly and
      completely. He said, ‘You have not prayed. If you were to die now, you
      would die on something other than the fitrah to which Allaah guided
      Muhammad  (peace and blessings of Allaah be upon him).’”
 It is essential
      to place the forehead and nose firmly on the ground when making sujood.
 It was reported
      that Ibn ‘Abbaas (may Allaah be pleased with them both) said: “The
      Prophet  (peace and blessings of Allaah be upon him) said: ‘I was
      commanded to prostrate on seven bones: the forehead’ – and he pointed
      to his nose – ‘the two hands, the two knees and the toes. And do not
      tie up your clothes or hair.’” (Narrated by al-Bukhaari, 779; Muslim, 490).
There is nothing wrong with making the sujood long, especially when
      praying alone, or in Salaat al-Kusoof (eclipse prayer) or in qiyaam
      al-layl (naafil prayers at night).
 It was reported
      from Asmaa’ bint Abi Bakr al-Siddeeq (may Allaah be pleased with her)
      that the Prophet  (peace and blessings of Allaah be upon him) prayed
      Salaat al-Kusoof (eclipse prayer). He stood and made his standing lengthy;
      then he did rukoo’ and made his rukoo’ lengthy; then he stood up and
      made his standing lengthy; then he did rukoo’ and made his rukoo’
      lengthy; then he stood up and did sujood, then he sat up and did sujood
      again, and made his sujood lengthy. Then he stood up and made his standing
      lengthy; then he did rukoo’ and made his rukoo’ lengthy; then he stood
      up and made his standing lengthy; then he did rukoo’ and made his
      rukoo’ lengthy; then he stood up and did sujood, and made his sujood
      lengthy; then he sat up and did sujood again, and made his sujood lengthy,
      then he finished.” (Narrated by
      al-Bukhaari, 812).
 It was reported
      that Hudhayfah said: “I prayed with the Prophet  (peace and
      blessings of Allaah be upon him) one night. He started to recite
      al-Baqarah, and I thought that he would do rukoo’ after one hundred
      aayaat, but he carried on. I thought that he would finish it and then do
      rukoo’, but he carried on. Then he started to recite al-Nisaa’ and he
      recited it all, then he started to recite Aal ‘Imraan, and he recited it
      all, at a steady and moderate pace. If he recited an aayah which mentioned
      tasbeeh (glorifying Allaah), he would glorify Allaah; if he recited an
      aayah which mentioned asking, he would ask Allaah; if he recited an aayah
      which mentioned seeking refuge with Allaah, he would seek refuge with Him.
      Then he did rukoo’ and started saying ‘Subhaan
      Rabbi al-al’Azeem,’ and his rukoo’ was almost as long as
      his standing. Then he said, ‘Sami’a
      Allaahu li man hamidah’ and stood up, and his standing was
      almost as long as his rukoo’. Then he prostrated and said, ‘Subhaana
      Rabbi al-A’laa’, and his sujood was almost as long as his
      standing.” (Narrated by Muslim,
      772)
 The Sunnah in
      sujood is to be level in sujood, as it was narrated from Anas that the
      Prophet  (peace and blessings of Allaah be upon him) said: “be level
      in sujood, and none of you should spread his forearms as a dog spreads
      them.” (Narrated
      by al-Bukhaari, 788; Muslim, 493).
Shaykh Ibn ‘Uthaymeen (may Allaah preserve him) said:
 This means that
      you should do sujood in a level way, not bunched up tight so that the
      stomach rests on the thighs and the thighs on the calves, and not
      stretched out as some people do when they prostrate, so that they are
      almost lying on their fronts. Undoubtedly this is a kind of bid’ah and
      is not Sunnah. It was not narrated from the Prophet  (peace and
      blessings of Allaah be upon him) or from any of the Sahaabah, as far as we
      know, that a person should stretch out his back in sujood. He should
      stretch his back in rukoo’, but in sujood he should raise his stomach
      and not stretch it out.” (al-Sharh
      al-Mumti’, 3/168).
 If a person
      does as the Prophet  (peace and blessings of Allaah be upon him)
      commanded, and he is prostrating on soil or a rough surface, then he may
      get a mark on his forehead. This may generate some pride in his heart, as
      mentioned in the question, but if a person’s heart is filled with
      sincere faith and he does what he does only for the purpose of seeking
      that which is with Allaah, then he will not care what people say about
      him. But if he deliberately tries to make a mark on his forehead that
      looks like the sign of sujood, then this is a kind of showing off and
      lying, so woe to him of the punishment of a painful Day!
 With regard to
      the aayah (interpretation of the meaning):
“… You see them bowing and falling down
      prostrate (in prayer), seeking Bounty from Allaah and (His) Good Pleasure.
      The mark of them (i.e. of their Faith) is on their faces (foreheads) from
      the traces of prostration (during prayers)….” [al-Fath 48:29]
 -- the correct meaning of the phrase “the
      mark of them is on their faces” is that this refers to the
      light of obedience and worship, and it does not necessarily mean that
      there is a physical mark on the skin in the place of prostration.
 Ibn Katheer (may Allaah have mercy on
      him) said in his Tafseer of
      this aayah:
 “… ‘the
      mark of them is on their faces from the traces of prostration’
      -‘Ali ibn Abi Talhah said,
      narratingfrom Ibn ‘Abbaas
      (may Allaah be pleased with them): ‘the
      mark of them is on their faces’ means their outward
      appearance. Mujaahid and others said that it means khushoo’ and
      humility. Ibn Abi Haatim said: my father told us, ‘Ali ibn Muhammad
      al-Tanaafusi told us, Husayn al-Ja’fi told us, from Zaa’idah from
      Mansoor from Mujaahid: ‘the mark of
      them is on their faces from the traces of prostration’ – he
      said: (this means) khushoo’ (humility). I said, I always thought that it
      meant this mark on the face. He said, That may appear between the eyes of
      one whose heart is harder than Pharaoh’s. Al-Saddi said: Prayer makes
      their faces beautiful. One of the Salaf said; Whoever prays more at night,
      his face becomes more handsome by day… Some of them said that a hasanah
      (good deeds) brings light (noor) to the heart and a glow to the face, an
      increased provision and the love of the people.”
 The point is, the fact that this mark is
      present on the skin and there is a change in the colour of the forehead,
      does not mean that a person is righteous and sincere. By the same token,
      if this mark is absent, that does not mean that a person is failing in his
      prayers. In many cases it has to do with the nature and sensitivity of an
      individual’s skin.
 Shaykh Ibn ‘Uthaymeen (may Allaah
      preserve him) was asked: is there any report to indicate that the mark on
      the forehead caused by sujood is a sign of the righteous?
 He replied:
 This is not one of the signs of the
      righteous; the sign is the light (noor ) which appears on the face, and
      being content and at peace, a good attitude, and the like.
 As for the mark made by sujood on the
      face, it may appear on the faces of people who do not even pray the
      obligatory prayers, if their skin is very soft and sensitive, and it may
      not appear of the faces of people who pray a lot and make lengthy sujood.
(Fataawaa
      Islamiyyah, 1/484)
In
      conclusion, then, if you are sincere towards Allaah and seek to earn His
      pleasure when you pray, then what people say will not affect you; in fact,
      their praise of you may be a kind of hastening of glad tidings for you in
      this world. So follow the Sunnah and do sujood properly, and then do not
      worry about whether people praise you or condemn you. We ask Allaah to
      make you sincere and to accept your prayers.
 And Allaah knows best.