Could be hemmoroids, acne, cists, or ingrown hairs. If its closer to the anus then its most likely hemoroids. If its not then I would use e cream or oil to help it heal.
This sounds like it might be a perianal abscess. Go to the wikipedia site below and see if what they describe sounds like what you are experiencing.
http://en.wikipedia.org/wiki/Perianal_abscess
Don't squeeze , scratch or rub these things. They are probably a staphylococcal infection or other bacterial infection. Do they look like a boil or crusty? Do they itch or hurt? You can try for a few days putting a topical triple antibiotic on them but if it doesn't start to clear up. If it does continue it for until it goes away. If it doesn't I would see a doctor. It is hard to clear this up because of the area they are in. Wash your hands often and anytime you touch the area as you can spread them easily to other areas. Wash all things that came in contact with the area, underwear, towels , wash rags etc. in hot soapy water.