Six types of lesion manifestations are included, and the main characteristics of each type of lesion are listed below.
Whitehead acne: a yellow, hardened mass of skin keratinocytes.
blackheads: the result of oxidation and darkening of whiteheads.
papules: small red bumps.
pustules: pustules appearing on the top of a papule.
nodule: a painful and hard lump on the surface of the skin.
Cyst: a lump that is painful under the surface of the skin and has pus to the touch.