How does a carbuncle look?

Large red bump: Looks like a large red boil or bump with yellow pus coming to a head. Can start very small as a pimple but then get infected and filled with pus and become very large like a golfball.

Carbuncle: A carbuncle is a skin infection that often involves a group of hair follicles. The infected material forms a lump, which occurs deep in the skin and may contain pus. When you have more than one carbuncle, the condition is called carbunculosis.