To prevent acne caused by wearing a mask, it is important to wash your face twice a day with a gentle, fragrance-free cleanser. Hydrating your skin regularly is also important in preventing acne. Make sure to wash your mask daily and avoid wearing a damp mask. Exfoliating your face once a week with a gentle exfoliant can also help. If acne persists, you can try using a product with PBO, like Clearasil BP, but make sure to start slowly and moisturize your skin well. Remember to test the product on a small area of skin before use, and be cautious as it can bleach fabrics. It may take 1 to 2 months to see the effects of the product.