Perspiration, or sweat, is your body's way of cooling itself, whether that extra heat comes from hardworking muscles or from overstimulated nerves. The average person has over 4 million sweat glands in their skin. Sweat glands are distributed over the entire body, except for the lips, nipples and external genital organs. The sweat gland is in the layer of skin called the dermis along with other "equipment," such as nerve endings, hair follicles and so on.