An abscess need not have a typical round shape.The acute presentation is very much in favour of abscess but may need Incision and drainage if it does not settle.
It is not a tumor,so rest assured.It seems like boils or furuncle. Boils are caused by infection of the hair follicle by staph aureus. Hair follicles that are blocked by greasy creams, petroleum jelly, or similar products are more vulnerable to infection. Bacterial skin infections can be spread by shared cosmetics or washcloths, close human contact, or by contact with pus from a boil or carbuncle.
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 keep on taking the antibiotics.If it forms a head the it needs to be drained.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.