@Azuza - Glycolic facial peels are considered to be a fairly gentle kind of chemical peel. I know a retinoic acid peel is one of the stronger kinds so that may be what your friend had done.
I'm starting to notice some fine lines and wrinkles so I'm considering having a glycolic peel done. I do have a few reservations about it so I'm definitely going to go with one of the less harsh types of peel. I think a glycolic peel might make a good choice for me.