Thought I should also mention since this concerns the front of my husbands jawbone. About two years ago, my husband got attacked and in the area from the lower just to the left of center and to his lip right in the center, he got cut open to the bone. The cut went completely through his lip and he almost had to have reconstructive surgery on it but was lucky enough to have a great surgeon on hand in the emergency room to be able to sew him up (at the second hospital, first doctor wouldnt even attempt to sew my husband up). Considering the injury, thought this might also give some ideas on possible explainations for the black spots since both were at the front of his jawbone.