Hi... I M Suffering From Cystic Acne And Almost Approached

Hi... I m suffering from cystic acne and almost approached all best doctors suggested to me.. my age is 26 and having oily skin. I m suffering from acne and pimples since age 17. I m applying sebogel acnecot eating several medicine but nothing works.... now doctor told me to apply Cosvate Gm. Will it work or u can prescribe me any medicine which I can eat to stop the formation of acne and pimples. My skin in very sensitive and even d small acne cover the big part around the acne and make it black.. plz advice me