It sounds a lot worse than it really is, when it ruptures it just speads out and
flattens so that it's not a huge bulging bump like it was before
it ruptured. It can be caused by an ingrown hair, a clogged gland, or bacteria that gets into the skin after shaving with a razor.
She told me to put a warm washcloth on it once or twice a day and it should go away in a couple of weeks. The soreness and swelling has already subsided, now it just looks like a flattened red lump.