It may caused by blocked sebaceous glands, swollen hair follicles, or trauma to the skin and it mainly occurs in the area like scalp, face, ears, and genitals.
It presents as painless small lumps or bumps
which arises under
the skin associated with redness and tenderness and increased temperature of the skin in the affected area.
If it does get infected then it can become painful. Sometimes, a grayish white, cheesy, foul smelling material may discharge from the bump or lump.