Hello Sir ,I Am 21 Years Old Nd Last Year

Hello sir ,I am 21 years old nd last year there is a lot of pemples on my face so consult with a dermatologist in a hospital nd there i treat 4 month nd ny all pemples are gone away ... bt afer 6or 7 months it again starts apear nd there is alot of red marks of pemples on my skin .... plz suggest now am what to do ??