Hi..
Can understand your concern..
As per your complain a hard lump on the jaw line after three weeks of wisdom tooth removal can be due to either any remaining tooth piece in the socket or any foreign body accidently left into the socket during wisdom tooth removal..
These can lead to infection and inflammation at a later stage leading to swelling, pain and difficulty in opening the mouth..
One more thing that should be considered is that you should also take care if the molar just before the wisdom tooth is infected and causing swelling..
I would suggest you to consult an oral surgeon and get evaluated by a clinical examination and
x ray to rule out the cause of swelling..
In case it is due to any infectious substance in wisdom tooth removal of the same followed by irrigation with
hydrogen peroxide,
betadine and saline can help along with antibiotics and painkillers..
In case if it is due to other molar treatment of the same by
root canal treatment or extraction can help..
Hope your query is solved..
Thanks and regards..
Dr.Honey Nandwani Arora..