See another derm. I also got fed up always getting a new prescription that didn't work. Retin-A also tore up my face. The resulting redness and peeling was more noticeable than the acne! It took me a few years, but I eventually got a bug up my bum and decided to find a derm who would give me Accutane. I can't tell you how nice it is to have no oil!! I honestly expected my face to get all flaky and sensitive like it was when I was using harsh topicals, but it's not like that at all.
My derm also told me that my acne wasn't severe enough to warrant Accutane, but I decided that I had suffered long enough.
Good luck to you!
If it's worth having, it's worth fighting for.