Pimples from past 3-4 months. A sudden?

The problem started 3-4 months back and has aggravated with time. Initially emerging as rash like figures, they started transforming into pimples and covered up my entire forehead. The rashes were same as you can see on my cheeks now. I used Mupirocin 2% at the initial stage. But when they started becoming pimple like figures, i was advised to apply Clindamycin gel 1%. It didn't help either. Now am using Benzoyl peroxide 5%, and still one subsides and another rises. Now i have started getting them on my face as well. Please help me. I am really scared. Why are no medicines working on me. I am 24 and have never ever had this kind of problems earlier. Also, the scars are making it uglier. Is there any solution of getting rid of the pimples for once and for all. Why is it happening all of a sudden? I have always have had a normal-dry skin.