Like hair, nails never stop growing. They must be cut from time to time. It does not hurt when people cut their nails as they are not innervated. The nails are made up of a protein called keratin which also makes up the main element of hair and skin. People paint their nails to make themselves look more attractive, usually females. On occasion nails can grow into the skin acting as a nidus of infection known as an ingrowing nail. They can hurt, so are often treated through medicine. The cutting and painting of the nails is called a manicure.