It looks like a boil or furuncle. Boils are caused by infection of the hair follicle by staph aureus. Bacterial skin infections can be spread by shared cosmetics or washcloths, close human contact, or by contact with pus from a boil or carbuncle. A boil generally starts as a reddened, tender area. Over time, the area becomes firm and hard. Eventually, the center of the abscess softens and becomes filled with pus. Finally, the pus "forms a head," which can be surgically opened or spontaneously drain out through the surface of the skin.
Apply warm compresses on the boil and keep the area clean.Drainage of the boil is done only when it becomes soft and forms a head.Take some over the counter pain reliever and consult a doctor for examination and antibiotics prescription.If there are recurrent boils,then pls get your blood sugar levels estimated.
Hope it helps.Take care and pls do keep me posted if you have any additional queries.