Bactrim acne????????

i had really bad acne back in november of last year so i went tot he doctor and got bactrim. so i took it for about 6 months and it was totally gone so i went off of it and within a month it came back and now its stronger then ever. I am also useing retin A topical before i go to sleep, and i went back on the bactrim and have been on it for about 3 weeks now and haven't seen no improvment yet. I was wondering if anyone out there had any suggestions of wut i could do, special remedys anything that would help would be greatly appreciated!