How to treat cold sores: These bumps need to be treated immediately by a dermatologist, according to Dr. Jaliman, so you don’t spread them to other areas of your skin or to other people. So they occur when the outermost layer of the skin fails to properly shed dead skin cells, causing htem to move deeper into the skin, instead. How to treat epidermoid cysts: Dr. Jaliman uses a cortisone shot to shrink the cyst under the skin, but keep in mind they these sort of bumps rarely cause symptoms and don't necessarily need treatment unless you want to get rid of them for cosmetic reasons.