Guidelines regarding changing the creation of Allah
Question

We know that the Messenger of Allah (blessings and peace of Allah be upon him) cursed the one who changes the creation of Allah. My question is: what is meant by changing the creation of Allah? I am confused, because I regard cosmetic products as changing the creation of Allah, but if the eyebrows are plucked, how can that be changing the creation of Allah, because the hair will grow back again? Some people say that this change is temporary. So I want to know what comes under the heading of changing the creation of Allah?  Also, we have the habit of using creams and moisturisers to soften women’s skin; are these things permissible?
Praise be to Allah.Firstly:
The religious texts indicate that it is haram to change the creation of Allah, and tell us that this is one of the commands of the Shaytaan by means of which he misleads people, as Allah, may He be exalted, says (interpretation of the meaning):
{They call upon instead of Him none but female [deities], and they [actually] call upon none but a rebellious Satan 
Whom Allah has cursed. For he had said, “I will surely take from among Your servants a specific portion 
And I will mislead them, and I will arouse in them [sinful] desires, and I will command them so they will slit the ears of cattle, and I will command them so they will change the creation of Allah.” And whoever takes Satan as an ally instead of Allah has certainly sustained a clear loss} [an-Nisa’ 4:117-119].
It was narrated that ‘Abdullah ibn Mas‘ood (may Allah be pleased with him) said: May Allah curse women who do tattoos and those who have tattoos done, women who have their eyebrows plucked, and women who file teeth for the purpose of beautification, changing the creation of Allah. News of that reached a woman of Banu Asad who was called Umm Ya’qoob. She came to him and said: What is this that I have heard about you cursing such-and-such and such-and-such? ‘Abdullah said: Why should I not curse those whom the Messenger of Allah (blessings and peace of Allah be upon him) cursed? Narrated by al-Bukhaari (4886) and Muslim (2125).
An-Nasaa’i narrated it as follows: The Messenger of Allah (blessings and peace of Allah be upon him) cursed women who do tattoos, women who file their teeth and women who pluck eyebrows, changing the creation of Allah, may He be glorified and exalted. It was classed as saheeh by al-Albaani in Saheeh an-Nasaa’i.
What is meant by filing teeth is filing them to look younger and to beautify the teeth.
An-Nawawi (may Allah have mercy on him) said: What is meant is filing between the front teeth. This is something that is done by old women and those who are close to them in age, to look younger and beautify the teeth, because this pretty gap between the teeth is something that is seen in young girls, but when a woman grows old her teeth grow bigger. Hence they file the teeth to make them look pretty and to give the impression that the woman is younger. This action is haram both for the one who does it and the one to whom it is done, because of these hadiths; because it is changing the creation of Allah, may He be exalted; and because it gives a false impression and is deceitful.
With regard to the words “women who file teeth for the purpose of beautification,” what is meant is that they do that in order to look beautiful. This indicates that what is haram is that which is done for the purpose of beautification. If it is needed for the purpose of medical treatment or to correct a defect in the teeth, and the like, then there is nothing wrong with it. And Allah knows best. End quote.
These reports indicate that the things mentioned – tattoos, plucking the eyebrows and filing the teeth – come under the heading of changing the creation of Allah.
Al-Haafiz Ibn Hajar said in Fath al-Baari: The words “changing the creation of Allah” refer the one who does tattoos, plucks eyebrows and files teeth. This also applies to adding hair extensions, according to one of the reports. End quote.
This hadith indicates that plucking the eyebrows is haram and the one who does that is cursed. We must submit to that, whether the reason for the prohibition is known or not.
There was a difference of scholarly opinion regarding this reason, and there are several views.
Al-Qurtubi (may Allah have mercy on him) said: Regarding all these issues, the hadiths state that the one who does them is cursed and that they are major sins, but there is a difference of opinion as to the reason why they are prohibited. It was said that it is because they come under the heading of deceit or that it is because they come under the heading of changing the creation of Allah, as Ibn Mas‘ood said. This is more correct, and it includes the first reason. However, it was said that what is prohibited is only that which is permanent, because it comes under the heading of changing the creation of Allah, may He be exalted. As for that which is not permanent, such as kohl, with which women beautify themselves, the scholars stated that it is permissible." (Tafseer al-Qurtubi 5/393).
These words of al-Qurtubi (may Allah have mercy on him) point to a guideline regarding what is meant by changing the creation of Allah, and indicate that it refers to a change that is permanent. This is a good guideline, by means of which we may reconcile between the prohibited matters that are mentioned in the hadith and permissible matters that no one says are prohibited, such as kohl and henna. But here we need to address what you mentioned in your question, which is that plucking the eyebrows is not permanent; rather the hair will grow back.
The response to that is that the hair that grows back will not grow back soon afterwards, so it comes under the same ruling as something that is permanent. Moreover, every time a hair appears, the woman who plucks her eyebrows removes it, so plucking becomes like something that is permanent, therefore it comes under the ruling on what is permanent.
Secondly:
That which is permissible is of different types:
1. That which is done for the purpose of medical treatment and removing defects, because of the report narrated by Abu Dawood (4232), at-Tirmidhi (1770) and an-Nasaa’i (5161) from ‘Abd ar-Rahmaan ibn Tarafah, that his grandfather ‘Arfajah ibn As‘ad had his nose cut off in the battle of al-Kulaab, and he wore a nose made of silver, but it began to stink, so the Prophet (blessings and peace of Allah be upon him) told him to get a nose made of gold. This hadith was classed as hasan by al-Albaani in Saheeh Abi Dawood.
Abu Dawood also narrated that Ibn ‘Abbaas (may Allah be pleased with him) said: The woman who does hair extensions and the woman for whom that is done, the woman who plucks eyebrows and the woman for whom that is done, the woman who does tattoos and the woman for whom that is done when there is no disease (that would justify doing that) are cursed. This hadith was classed as saheeh by al-Albaani in Saheeh Abi Dawood.
Ahmad (3945) narrated that Ibn Mas‘ood (may Allah be pleased with him) said: I heard the Messenger of Allah (blessings and peace of Allah be upon him) forbid plucking facial hair, filing teeth, adding hair extensions and tattooing, except in the case of disease. Shaykh Ahmad Shaakir said: Its isnaad is saheeh.
Ash-Shawkaani (may Allah have mercy on him) said: The apparent meaning of the words “except in the case of disease” suggests that the prohibition mentioned only applies if these things are done for the purpose of beautification, not for the purpose of treating disease and sickness, in which case they are not prohibited." (Nayl al-Awtaar  6/229).
2. That which is done to remove something that has happened and caused deformity. That includes freckles, moles and the like, because this is restoring that which Allah created, and it is not changing the creation of Allah.
Ibn al-Jawzi said: As for medicines that remove freckles and make the face beautiful for the husband, I do not see anything wrong with that.
That also includes using creams to soften the skin, which is restoring it to its original condition.
3. That which is done for the purpose of temporary beautification, that does not remain and does not change the original features, such as kohl, henna, rouge, and lipstick. Kohl and henna were well known and widely used among women at the time of the Prophet (blessings and peace of Allah be upon him), as were saffron and other colours that were mixed with women’s perfume. Hence there is nothing wrong with using cosmetic products, if they are free of harmful materials.
According to the hadith of ‘Abd ar-Rahmaan ibn ‘Awf (may Allah be pleased with him), he got married and came to the Prophet (blessings and peace of Allah be upon him) with traces of yellowish perfume on him. Narrated by al-Bukhaari (5153) and Muslim (1427).
The scholars interpreted that as meaning that the traces of yellowish  perfume got onto him from his wife, because it is proven that men are not allowed to use saffron (as perfume).
And Allah knows best.