Prescription isotretinoin, we used Epuris or Accutane. I refused them at the begainning for my kids... but finally, at high school, they had to get that to get under control. Bad acne can hurt kids confidence and selfsteem very badlly...
My old one did not start until he was in Uni, when come to the younger one, I started at grade 10....
However, do be careful with the sideffects, I did a lot reserch before starting them, luckily, my kids did not have too much of them, mostly the dryness, but they managed ok, if you don't start in Winter, you will be easier...
My younger finished in 6 months, and with beautiful results, and for old one not that easy, I do not know if that is because the younger one started earlier, in Grade 10 made the difference...