Small little bumps on my right arm they don't go away but they get hard?

Keratosis Pilaris: Keratosis pilaris is a common skin condition in which a protein in the skin called keratin forms hard plugs within hair follicles. Causes, incidence, and risk factors keratosis pilaris is harmless (benign). It seems to run in families. It is more common in people who have very dry skin, or who have atopic dermatitis (eczema). The condition is generally worse in winter and often clears in the summ.