<s>[INST] painful lump about a centimeter in diameterin my underarm for the past 3 days. it began as a little dot that hurt a bit to touch and has grown into its current form. feels a bit hard to touch. is it an abscess? WHat is usually the treatment for this. [/INST] Hello! Welcome to HCM.You havent mentioned your sex, presence or absence of fever..This can be an enlarged lymph node or abscess or sebaceous cyst...Local examination tells us the exact diagnosis, as per its consistency, presence or absence of punctum, mobility etc.If required, FNAC - fine needle aspiration cytology is advised.Treatment is done accordingly, usually excision biopsy if there is no suspicion of malignancy otherwise search for primary.Hope this information is useful to you.Wish you a good health.Thanks. Regards. </s>