Hi,
This could be folliculitis.Folliculitis is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin.
Folliculitis starts when hair follicles are damaged by friction from clothing, blockage of the follicle, shaving . In most cases of folliculitis, the damaged follicles are then infected with the bacteria Staphylococcus (staph).Most carbuncles and furuncles and other cases of folliculitis develop from Staphylococcus aureus.
Topical antibiotics such as mupirocin ointment applied to the affected raea twice a day for 5 days is sufficient to cause a resolution.
This may not be anything serious. It should be gone in a week's time.
ref:http://en.wikipedia.org/wiki/Folliculitis
You need to see a doctor it may be a boil underneath your skin and he can drain it or lance it.
Did you just have a baby with in the last 1-2 years?