DD14 tried it, had mild acne on the sides of her face and forehead. Cleared it up, she hasn't used anything in months. No more pimples.
DD13 tried it, same issues, acne on forehead and sides of face.. Worked great for about 2 months then came back. Proactive no longer works. I have bought just about every OTC cream since then, but nothing works. Her case isn't enough to warrant a dermatologist visit and she can cover it up with makeup (Neutrogena which has acne meds in the makeup). I'm sure it will clear up on it's own. DH had it when he was a teen and grew out of it.
So in the same family, it worked differently. I would recommend giving it, or one of the kits you can buy at WM at shot. I believe they both have the same active ingredients.