Allah has cursed one who has cauterised it (on the face).
Sahih Muslim Book 37, Hadith 163
← Previous Hadith This hadith has been reported on the authority of Jabir b. 'Abdullah through another chain of transmitters.

Sahih Muslim Book 37, Hadith 162 Next Hadith → By Allah, I do not cauterise (the animal) but on a part at a distance from the face, and commanded (for the cauterisation) of his ass and it was cauterised on the buttocks and he was the first to cauterise on the buttocks.

Sahih Muslim Book 37, Hadith 164