I had a horrible rash years ago which was poorly treated by my GP of the time but I got wonderful results when I finally went off to the dermatologist. Ask for a referral, or if not, ask your doctor to find another GP in your area who specialises in skin conditions. It may not be acne at all (mine - which looked like acne - turned out to be some thing quite different in the end).

BTW - hint for pimples, Blackmores has this fabulous pimple gel, it works like a dream on any pimples, boils, cold sores, or any other pustulous outbreaks, it comes in a tiny little glass vial, contains tea tree and other herbal oils and works better than anything I know. Smelly, but good. The pimple sort of calms down and then dries out over 1-3 days (depending on the severity). It might bring you some short term relief?
HTH