Superficial Acne: 1st degree: black and white spots. 2nd degree: papules and pustules.
Deep Acne: 3rd degree: pustules and nodules. 4th degree: nodules and cysts.

How does acne develop?
Sometimes hair, tallow and skin cells get together and form a plug in the pore. The bacterium that is on the pore causes swelling. It is originated during puberty. Is more severe in men than in women.