The human skin all over the body is covered with the dermis and the epidermis, two outer layers that protect the skin. Lips are made up of a special mucous membrane. Many nerve fibres too are directed to this region. The mucous membrane on the lips, also known as the cutomucosal layer, is delicate and is supplied with many blood vessels. Hence the lips look red. Also, they possess a certain kind of pigment. The lips of fair persons are red, but those of dark people may look black or violet.