I have noticed some teenagers (including a niece) who once had such clear skins suddenly get acne. I know it’s a hormonal thing, and they can’t help it. I just know that they can be quite uncomfortable with the situation, though, and might even find an acne treatment that will work for them. I was lucky, since I never had that problem while I was in high school. However, I noticed that after I delivered my son, I got these infuriating pimples every now and then! So now, it’s my problem, too.