Adult Acne--What To Do About It?

A friend of mine is absolutely beautiful: tall, thin, and blond--you get the picture. I would hate her if I wasn't crazy about her as a friend. But she says she has acne, even though for the life of me I can't see it. She must cover it up well with makeup. She has been asking around about adult acne treatments,and I have to say I don't know anything about, because I don't have acne now. She goes to the dermatologist, but so far nothing has worked. I am sure she will have some kind of treatment.