They tend to pop up on the face, chest, belly, and back ... "A boil is a generic term for a pus-filled bump under the skin," says Dr. Gohara. Causes of boils: "Pus in the skin generally connotes ...

Others make their arrival known long before they ever come to the surface by causing a painful lump. The latter is typically a big pimple under skin's surface, aka a blind pimple, and they're ...