Your cats complexion has two different types of glands in a dermal layer. The sweat glands that keep the body temperature in balance and the sebaceous glands that exude a greasy materials called sebum. The sebum is usually a source of the most common cat skin diseases that people know as feline acne. Sebaceous glands are mixed together in large numbers in the skin on that chin, lips, top surface from the base of that tail, prepuce and scrotum associated with cats. Sebum secretions with these glands are primarily supposed to protect hair versus water and keep the skin supple.