Is it effective to use regular table salt for acne?

Don't expect help: There's no reason to think this will be effective. Nobody can or should test the hundreds of "pop" acne remedies. What I do know is that topical benzoyl peroxide is the best non-prescription rx, and that any competent primary care physician can clear up all but the worst acne. If you're responsible for a teen's health, it's your duty to get him/her seen.