Hello! Welcome to HCM. This seems to be more likely a hematoma. Hematoma is nothing but clotted blood under the skin. Nothing needs to be done as it resorbs spontaneously. Serratiopeptidase like enzymes can be taken to make the resorption faster. Watch for infection, which is suggested by presence of fever, pus discharge from nipple.. in this case incision & drainage of the abscess (pus) is necessary to be done by your doctor along with prescription of antibiotics. If there is suspicion of malignancy (cancer) on clinical examination (unlikely in your case), I advise FNAC - fine needle aspiration cytology for confirmation of diagnosis. Hope this helps. Wish you speedy recovery. Thanks. Regards.