Milia are deep white bumps that form when skin cells become trapped rather than exfoliated naturally. They turn into tiny cysts that look like whiteheads or bumps below the surface of the skin. Milia can occur on the skin or on mucous membranes like the inner surface of the cheek or the border of the lips and around the nose.

They are extremely common in children, and those with oily skin are more prone to milia than others. With that said, they can effect combination and even dry skin as well. Milia need to be extracted manually, but the good news is that according to dermatologist Zoe Friedman, milia can be prevented by exfoliating frequently at home.

Exfoliating helps keep your face clean while preventing clogged pores—when done properly. Do not abrasively scrub your face; simply use a gentle exfoliating cleanser twice a week. Also, when you're in the sun, opt for an oil-free sunscreen.

Remember that picking at milia on your own can cause them to return. If they persist, contact your dermatologist, who can administer microdermabrasion or glycolic peels.