A cyst usually presents as a small bump or lump beneath the skin surface. It occurs when the lining of the hair follicle gets blocked. The cyst sac becomes filled with a cheese-like whitish material that can sometimes ooze out onto the skin’s surface. There are many types of cysts and they can appear almost anywhere. They are most common on the scalp, neck, back, and face. They are sometimes mistaken for a lipoma. A cyst can rupture causing it to become inflamed (red and painful). Occasionally cysts become infected, discharge pus, and resemble a boil. Cysts may be removed with surgery under local anesthetic. Cysts that are inflamed or infected also may require a antibiotic.