Our dermatologist did not recommend ProActiv for my daughter. He said that the ingredients aren't as fantastic as the price would indicate. He recommended Murad's acne products. We went and bought them at Ulta (there's a 30 day sample pack so you can try a little bit of everything before committing to buying a full size of any of the products). I also bought her a Clairsonic. I have to say, my daughter's skin is beautiful now. She doesn't break out at all, and before we started this, she had typical teen/hormonal breakout issues.
If your daughter has cystic acne at all, maybe look into Accutane. I know most dermatologists are hesitant to prescribe it to teens, but I was on it in my early 20s and it worked wonders. My skin was PERFECT for about 10 years after that (until I had kids, haha).