I have these bumps under my arms that are filled with pus and blood. they are extremely painful and they swell up too.what is this?

Bumps under arm: These bumps can be either a blocked up sweat gland in your armpit; these tend to be fairly small, around 1/4 inch. Certain deodorants can irritate the pores and cause them to block up. If there are multiple larger lumps, you may have a condition called "hydradenitis suppurative" where the glands get recurrently swollen, tender, and often actually drain pus. See an md. Treatment is controversial.

Hidradenitis: Staph or other bacterial infections can cause this type of bump. Another condition known as hidradenitis suppurativa can also cause these bumps, often in underarms, groin, and sometimes under breasts. It can be more difficult to clear up than a simple bacterial infection.