Why did my skin change so much as a teenager?

almost all through middle school my skin was clear, I had an even skin tone, and it wasn't too oily or too dry, I didn't need to wear any foundation or powder, but as soon as I got to high school my skin tone started getting more red, splotchy and uneven, I got really bad breakouts, I stared getting really oily in my T-zone and flaky dry in the other areas, and now Im super self conscious about my skin. I went to the dermatologist a few months ago and I got prescribed 3 topical creams and so far it got rid of the acne, but there are still a bunch of red spots where all the acne was, so now I have red polka dots all over the sides of my cheeks, and my skin tone is still really uneven! WHEN WIlLL THIS GO AWAY?