Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain numb feeling of the chin can be due to traumatic
injury to the nerves during the extraction procedure leading to
numbness of the areas supplied by those particular branches of the nerves..
If the injury is mino then nerve will repair and numbness will resolve..
But if there is complete damage or severing of nerve then the numbness can be permanent..
Consult a Neurophysician and get evaluated and a thorough clinical evaluation and investigations like
x ray or
MRI SCAN can help in diagnosis and treatment can be done accordingly..
As far as the lump is concerned it can be due to
Hematoma formation post extraction and at times Hematoma gets localized and take a long time to resolve and it gradually resolve on its own.
But get the confirmation by an Oral Physician and get treated accordingly..
Hope this helps..
Regards.