Suggest Treatment For Cystic Acne Along With Pigmentation On Forehead

I get cystic acne often on my face. dr prescribed me spironolactone 100 mg daily. I am taking it from last two months . now no acne but pigmentation on my forehead and cheeks. I don t have severe acne but one cystic acne at a time. what should I do for my acne. pls prescribe something which doesn t not cause malasma/ hyper pigmentation. I apply spf 50 sunscreen every day and avoid sun completely.