Thanks for your query. I have gone through your query. The lump can be because of the inflammatory swelling secondary to trauma. The other possible cause can be because of the fractured bone. Nothing to be panic, consult a general physician and get it evaluated. You need get a radiograph done to confirm the diagnosis. Mean while you can take analgesics like diclofenac and antiinflammatory drugs like serratiopeptidase (if you are not allergic). I hope i have answered your query. Take care.