Hello, Thanks for your query. From description , this hard lump most probably formed due to haematoma formation (collection of blood) which might get fibrosed or calcified. It will take few weeks to months to get disappear. I suggest you to consult an orthopaedician nearby for a detailed examination of swelling. You may get the X-ray of the area affected under his/her guidance. Meanwhile give hot fomatation over it, You can take Tablet Motrin 1 tablet with food as and when required (upto 4 tablets daily). I do hope that you have found something helpful and I will be glad to answer any further query.