Boils: "BoilsWHAT YOU SHOULD KNOWA boil, known medically as a furuncle (FUR-un-cul), is an infected hair follicle (the place in the skin where a hair is formed). Boils are common and grow deep into the skin's layers. They are usually found on the face, neck, breasts, and buttocks. With treatment, a boil can be cured in 5 to 10 days.CausesBoils are caused by bacteria. If a boil breaks open, the bacteria may spread to nearby skin, causing new boils to form.Signs/SymptomsA painful, pus-filled, red bump will appear. A boil can appear suddenly and become very painful within 24 hours. "