He noticed the smell of maniy on his clothes after he woke up; does he have to do ghusl?
Question

                I have a question and I hope you can answer it. One day I woke up and I noticed the smell of maniy, but I checked myself and could not see any trace of it, so I thought there was no need to do ghusl, because maniy is something clear and well known. Three days later the same thing happened to me, but I found traces of it, so I did ghusl. That led me to wonder whether there had been any maniy present on the first occasion, but I had not noticed it. Do I have to repeat the prayers of those three days?.
Praise be to Allah.
    Firstly: 

    If a person has an erotic dream but does not see any maniy, 
    he does not have to do ghusl, according to scholarly consensus. If he sees 
    maniy but does not remember having an erotic dream, then he has to do ghusl, 
    according to scholarly consensus. What counts with regard to ghusl being 
    obligatory is the presence of maniy or traces thereof. 

    See the answer to question no.
    22705 and
    111846 

    If you checked your clothes and did not find any trace of 
    maniy, then you do not have to do ghusl just because you noticed the smell 
    of maniy. A similar smell may be detected on clothing after sweating. 

    It was narrated that Umm Salamah said: Umm Sulaym came to the 
    Messenger of Allah (blessings and peace of Allah be upon him) and said: O 
    Messenger of Allah, Allah is not too shy to tell the truth. Does a woman 
    have to do ghusl if she has an erotic dream? The Prophet (blessings and 
    peace of Allah be upon him) said: “If she sees water (a discharge).” 

    Narrated by al-Bukhaari, 130; Muslim, 471 

    It was narrated from Abu Sa ‘eed al-Khudri that the Prophet 
    (blessings and peace of Allah be upon him) said: “Water (ghusl) is for water 
    (maniy).”

    Narrated by Muslim, 518.

    It was narrated that ‘Aa’ishah said: The Messenger of Allah 
    (peace and blessings of Allaah be upon him) was asked about a man who 
    notices some wetness but does not remember having an erotic dream. He said, 
    “He should do ghusl.” He was asked about a man who thinks that he had an 
    erotic dream but does not see any wetness. He said, “He does not have to do 
    ghusl.” Umm Salamah said, “O Messenger of Allaah, does a woman have to do 
    ghusl if she sees something like that?” He said, “Yes, women are the twin 
    halves of men.” 

    Narrated by al-Tirmidhi, 113; Abu Dawood, 236; classed as 
    hasan by Shaykh al-Albaani in Saheeh Abi Dawood. 

    An-Nawawi (may Allah have mercy on him) said: Ibn al-Mundhir 
    narrated that there was consensus on the idea that if a man sees in his 
    dream that he ejaculated or had intercourse, but does not find any wetness, 
    then he does not have to do ghusl. And Allah knows best.

    End quote from Sharh al-Muhadhdhab, 2/161 

    Ibn Qudaamah (may Allah have mercy on him) said: If he dreams 
    that he ejaculated but does not see any maniy, then he does not have to do 
    ghusl. Ibn al-Mundhir said: The scholars from whom I learned were 
    unanimously agreed on that. … But if he wakes up and sees maniy, although he 
    does not remember having an erotic dream, then he has to do ghusl, and we do 
    not know of any difference of opinion concerning that either. End quote from
    al-Mughni, 1/130. See also Fath al-Baari by Ibn Hajar, 1/389 

    And Allah knows best.