When I was a pre-teen, over-the-counter medications did not work for me. Instead, I used hydrogen peroxide. It is much cheaper and more effective. I don't think acne is preventable.
Acne can't be pinched. Acne occurs from some foods such as nuts. A preteen boy's skin has much more oil than an adult. Too much cleaning of the face with soap also causes acne. My household never got acne because we eat yogurt at every meal. This helps avoid acne.
