A milium is a micro-cyst (1 to 2 mm in diameter) composed of a cluster of keratin (dead cells) trapped under the outer layer of the skin. It can have a whitish or yellowish appearance. Often present in an isolated way, on the face, the neck or the hands, but one can also find grains of milium in plates, about fifty, even a hundred small lesions, mainly on the ears, the cheeks, or the eyelids. The milium grains are quite hard to the touch, almost like a small piece of sand under the skin, and do not show redness or inflammation like whiteheads or acne-related spots and cannot be pierced and drained.
When you see grains of milium on the surface of your skin, it's a sign that your skin is not exfoliating. In other words, it means that the skin is not properly ridding itself of dead skin cells. Milia are completely benign and do not pose a health risk. They usually disappear without any intervention, but it can take a long time, even months. The unsightly appearance of milia makes some people want to get rid of them as soon as possible.