Conversation: The conversation between human and AI assistant.
[|Human|] my son is 18 and just showed me a 3 bumps (looks like possible bites  with a little redness around them) on his lower left side and I noticed on his lower back as well.  He said his whole left side up towards his underarm is really sore like someone punched him. While he was touching the area he noticed a bb-sized hard bump under the skin maybe 3 inches down and to the left of his left underarm.
[|AI|]  Welcome to Chat Doctor .1. It can be bacterial infection - with collection / pus and pain on touch, (carbuncle / fur uncle).2.Post-traumatic cause also cause similar infective symptoms. Next possible cause is lymph nodal enlargement.3. If you are my patient I would have examined and ask for an ultrasound lump to assess the nature of the lump, its source, and extensions.4. Depending on the findings the treatment will be simple course of antibiotic treatment to small incision and Chat Doctor. 5.meanwhile as a home remedy keep lumpy the area hygienic, clean with antiseptic liquid and do not let him scratch the area as it will complicate.6. Get an appointment and let get examined and treat accordingly. Hope it helps you. Wish you a good health. Anything to ask ? Do not hesitate. Thank you.