Did you check your sex hormone levels in hospital?
As far as I know, birth control pills are used to control acnes which are caused by high male hormone in women.
Maybe your sex hormone levels are normal. My personal suggestion is that going to hospital and ask the doctors if Isotretinoin will suit for your condition. I heard that doctors in USA try to avoid 'Isotretinoin' in acne treatment, for its notorious side effect. However, doctors in China will use 'Isotretinoin' and try to avoid birth control pills. For my personal experience, the side effects of birth control pills are much more awful than Isotretinoin.