Is it permissible to use botox?
Firstly:
There is nothing wrong with breast implants or enlargement for one who has had a breast removed or who is suffering because they are small, because that comes under the heading of removing a fault or restoring something to the way it was created by Allah.
The evidence for that is the report narrated by Abu Dawood (4232), al-Tirmidhi (1770) and al-Nasaa’i (5161) from ‘Abd al-Rahmaan ibn Tarafah, that the nose of his grandfather ‘Arjafah ibn As‘ad was 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 hadeeth was classed as hasan by al-Albaani in Saheeh Abi Dawood.
Please see the comments of the scholars concerning this matter in the answer to question no. 138273 and 108860.
Secondly:
It is permissible to use botox if it is free from harm, because the Prophet (blessings and peace of Allah be upon him) said: “There should be neither harm nor reciprocating harm.”
Narrated by Ahmad (2865), Ibn Maajah (2341) and classed as saheeh by al-Albaani in Saheeh Ibn Maajah.
And Allah knows best.