Conversation: The conversation between human and AI assistant.
[|Human|] Hi, I fell down a flight of stairs in the outside stair well of a flat block 3-4 weeks ago. I landed on the top of my bum/lower back, at time there was a lot of swelling and after a few days a large purple bruise. Once the bruising faded I noticed a large oval shaped lump on my bum with yellow bruising around it, and since then its never reduced. Its hard to touch and quite painful after sitting down for a long time. Any suggestions to what this could be and whether I should see a doctor?
[|AI|]  Hi and thanks for the query, I do think you need to see the doctor. The color and the fact that it is still painful deserves that a collection of some pus inside be checked for. It is simple through a needle aspiration. In case of pus, a needle aspiration would be sufficient. If not, this should simply be the consequences of the trauma, with either mild bleeding into the tissue and swelling. In this case, you should be ok with time, But in case there is an infectious process going on inside, an incision could help. I suggest you see your doctor to be quite sure of the status. Thanks and kind regards.