It could be something as simple as a sebaceous cyst, an infected,
ingrown hair follicle, a collosal zit or perhaps a growth of some sort.
Either way, you need to visit with your physician. A large cyst or boil, can be removed or lanced to relieve the pressure. Your doctor may also elect to put you on antibiotics to reduce the chance of a staph or other dangerous infection. If it is a growth of some sort, then it needs to be removed and biopsied to check for malignancy.