Why is my acne getting worse?

Okay, so I've always had the typical break outs with one or two average zits. I'm 17, so it happens I understand that. I still washed my face day and night and medicated it. I believed my acne was bad, so I went to the dermatologist and was prescribed some average liquid. Well, eventually I ran out and just went back to my normal face wash. My brother on the other hand has ALWAYS had bad acne and never washes his face. Recently my face has completely broken out to the point where my family and friends are recommending me face washes. I really need to figure out why I'm breaking out, but I don't have an extra $100 to go to the dermatologist.