Old line oral surgeons, usually the ones most recommended by dentists and the people dentists get their implants done, recommend 3 months for an extraction to heal. They can take a very long time sometimes. So it could just be that it hasn't had time to heal yet.
I completely understand what you are going through, I had a lump on the bottom of my jaw a few weeks ago that had me worried. It ended up being a lymph node that was a bit swollen, don't worry...you should go to your doctor and have him take a look at it. I'm sure it's just swelling from the infection and the removal of the molar. Hang in there, I'm sure everything is fine. Best of luck!!!