My acne is getting worse!! What do I do!!?

I'm 17 and I've been using Benzoyl Peroxide and Clindamycin Phosphate for the last 2 years and they would always help clear my face up a little but never fully cleared it all the way up. Then a couple weeks ago my doctor prescribed me Differin. Here's how my daily schedule would go. In the morning I wake up, shower, and then wash my face with Olay Foaming Face Wash (soap and oil free) and then use the Clindamycin Phosphate (liquid) and rub it all over my face. Then at night, I wash my face with the same Face Wash and then use the Clindamycin Phosphate, wait till it dries, then use the Benzoyl Peroxide on more of the problem areas, and then put on the Differin also on the problem areas. I've been doing this since I got the Differin and lately I've been getting these nasty huge pimples. Is it because of the combination of all the acne systems? Or is it just the Differin doing its job? And should i just do the Differin or keep on using the other two also? And how do you know if you have acne scars? I ask this because I have these small areas on my cheeks that are real flattened looking acne but they rarely go away. Any answers or solutions would be greatly appreciated! Thanks!!