Does anyone know what could cause a hard lump under the left side of my jawbone? It feels like it is right up against it.

A few weeks ago the whole side of my mouth was hurting. I took two rounds of antibiotics. Following that, the dentist xrayed and couldn't see a sign of infection. The nurse practioner checked for an ear infection, but that was fine. Now here it is probly a month later and I have this knot.

It hurts 'some' but not really bad. Hurts more when I push on it.

Any ideas as to what it could possibly be caused from?
Thanks!