Hello, Thanks for your query. From description it seems to be soft tissue injury . Knot might be due to haematoma formation(collection of blood). You need an x-ray to rule out any bony injury. I suggest you to consult an orthopaedician nearby for a detailed examination. You may get the X-ray of the area affected under his/her guidance. Beside icing and elevating it, you can take anti-inflammatory drug like motrin to reduce pain and inflammation. Avoid putting weight and rest well. I do hope that you have found something helpful and I will be glad to answer any further query. Take care