Huge zit or boil under the armpit?

I ume you are shaving with a disposalable razor. To prevent boils, I recommend using a NEW razor each time you shave your underarms. What happens is your pulling hair focllicles and bacteria can get trapped in there and cause the bumps. To relieve the pain, try putting some hot packs or a hot wash cloth on the area and see if it comes to head, cause you want it to drain.