Having impacted wisdom teeth removed is not a casual procedure. There is a lot of bone removal and then you're expecting a quiet recovery as if you had a haircut.. A post extraction infection usually involves tiny bits of bone in tooth that did not get flushed out of the extraction site because it is in extremely inaccessible.A second reason for post operative pain is minute fractures of the bone socket wall that are undetectable visually, and simply are part of the healing process due to the process of having to section a tooth and remove parts of it. The analogy is like digging a small hole in front of your house and trying to remove all the plumbing through that hole.
Swelling after wisdom teeth removal
The firmness you feel may just be the remodeling of the bone in the area. Sometimes this persists longer than the normal couple weeks if you had a post Operative infection like you describe. If there is no pain then you are probably healing. If there is pain you should see the Oral surgeon and possibly get a CT scan to make sure there is nothing else going on