I posted this so many times I finally thought to save a copy:
Our son had pretty bad acne on his back. Here's what he did to get rid of it:
Clean sheets at least once a week, washed in hot water. More frequent change is better. If this is more than the laundry-doer at your house can handle, wash 'em yourself.
Clean towels, same.
Shower once a day, soaping affected area gently but thoroughly with Neutrogena soap formulated for acne.
A back brush with fairly soft bristles to help reach the middle. No hard scrubbing!
Second quick shower soon after any serious sweat-producing activity, using any antibacterial soap.
Scrupulously clean shirts. No second wearings, and change it if you sweated in it. If the shirt can take it, hot or at least warm water laundering. Again, wash 'em yourself.
If you’ve got long hair, keep it very clean, pulled back so it covers only a part of the back when not in public. In heat, a braid. Overnight, a braid.
Short periods of exposure to sun, not enough to show a tan line. (15 minutes a couple times a week helped a lot.)
For our son, it seemed to be largely a matter of more consistent hygiene than his teenage self was doing. He still gets the occasional zit on his back, but the norm is essentially clear skin there. (And he does his own laundry!)
· 4 months ago