Numbness in the left side of my face under my eye, towards my mouth on and off. can this be caused by tmj or b-12 deficiency?

Dental visit: Advise you start with a dental visit to xray and eliminate teeth as the cause of the numbness

Possibly: Could also be tooth/teeth infection, gum infection, neurological disorder, infected sinus, and lots of other possibilities. Need both dental and medical work-ups, including appropriate x-rays and lab tests. Please schedule both examinations now. Important to not put this off.

Very unlikely: There are lots of other more likely causes and any unexplained numbness needs to be evaluated asap. First a dentist to rule out any dental causes, followed by a visit to your primary care physician if not dental in origin.