Can you use clotrimazole cream on your back for your acne?

Won't work: It's an antifungal. If your "acne" is really pityrosporum infection / tinea / folliculutis, it will work wonders. If it's real acne, get with your personal physician. Acne on the trunk usually requires systemic rx -- a real antibiotic or isotretinoin. The latter isn't for the faint-hearted but may be what you need to get clear. Best wishes.