The small white bumps caused by trapped keratin are called milia.
Milia are tiny, keratin-filled cysts that form just beneath the epidermis. They commonly appear around the nose, cheeks, and eyelids, where they look like firm white or pearly beads. A single bump is a milium; the plural form, milia, is the term most often used for multiple bumps.
Milia develop when dead skin cells do not shed normally and become trapped under the surface. They can occur in newborns, children, and adults. Newborn milia are especially common and often disappear on their own within a few weeks. In adults, milia may arise spontaneously or after skin injury, burns, blistering, prolonged use of steroid creams, or heavy ointments.
They are often mistaken for whiteheads, but the conditions are different. Whiteheads are acne lesions involving a blocked hair follicle, while milia are keratin cysts and generally lack the inflammation associated with acne. Dermatologists can remove persistent milia by opening the surface and extracting the contents; squeezing them at home can injure the skin.