than the normal surrounding skin. This darkening is due to excess melanin pigment that deposits in the skin.It can also persist in the location where an acne pimple used to be.
Most over-the-counter skin bleaches lighten and fade darkened skin patches by slowing the production of melanin so those dark spots gradually fade to match normal skin coloration. If it persists, it is best to see your dermatologist for further evaluation and management.