If you develop breakouts from wearing a mask, you’re not alone. This condition, known as “maskne” (mask acne), is a common side effect of using a mask. Maskne doesn’t simply cause pimples, though. It may also result in skin issues, including redness, bumpiness, and irritation. Because maskne can involve various skin conditions, the exact cause of your symptoms may vary. In most cases, maskne is the result of clogged pores. You already have oil, bacteria, and dead skin cells on your skin. But when you wear a mask, these substances can build up more and block your pores.