Furuncle is a skin abscess, a painful bump that forms under the skin - it is full of puss. A carbuncle is collection of boils that develop under the skin. When bacteria infect hair follicles they can swell up and turn into boils. Such abscesses respond to hot packs and lancing, rather than antibiotics, experts say. Antibiotics may be used if the infection spreads into a deeper layer of skin. Boils come on rapidly as pink/red bumps about ½ to ¾ inch in diameter, they are often painful. The surrounding skin is typically red, inflamed and tender. The bump fills with pus within a few days and grows. The bigger it gets the more painful it becomes. According to the NHS (National Health Service), UK, boils can sometimes become as big as ping-pong balls. They generally go away within one or two weeks, but can take longer. A large boil may leave a scar.