A boil is technically called a furnucle. A furuncle (boil) is a skin infection involving an entire hair follicle and nearby skin tissue, and boils are actually failry common. Boils are caused by the staphylococcus bacteria or other bacteria or fungi, which are normally found on the skin surface but enter the skin through a hair follicle to cause infection.

It's possible to full recover from a boil. In fact, furuncles may heal on their own after an initial period of itching and mild pain. More often, they progress to pustules that increase in discomfort as pus collects. They finally burst, drain, and then heal spontaneously.

You can help treat a boil by applying a warm moist compresses to encourage furuncles to drain, which speeds healing. Gently soak the area with a warm, moist cloth several times each day. Deep or large lesions may need to be drained surgically by a doctor. Never squeeze a boil because if it bursts, this can spread the infection and make it worse. Additionally, good hygiene prevents the spread of infection. Do not re-use or share washcloths or towels or clothing, for example. Wash all surfaces that come into contact with infected areas in very hot (preferably boiling) water.

If you need professional help, you can see a dermatologist.

awesum thanx so mucheroos! so i got this because im dirty? thats embarrassing. i dont think im that dirty compared to other peeps. but if its because im not a healthy person, thats so true! all i eat is pretty much junk food. so im not really sure why i got this boil and why behind the thigh...

Nothing to be embarrassed about although I would also suggest you get yourself a check up. Not saying, you "got this because you are dirty", but if this boil is as large as you described 5".....I'd say have a physican look at it. You said it yourself......... your not a helathy person........you need to take better care of yourself. Eat a more healthy diet. Not sure anyone can pinpoint why and where someone may get a boil from. If so, I'd be happy to learn more! Hope you get better soon!