Had a tooth infection which was treated dec 14th but before being treated my chin and left side is all numb - i am on penicillin will this go away.

Dental infection: Go back and let the dentist see this. Either the swelling involved the nerve root secondarily or you had a primary infection of the nerve producing this numbness. You need to be examined to be diagnosed. Good luck.

99% of the time yes: If the tooth has been treated by extraction or root canal and the abcess resolves, the pressure on the mandibular nerve dissipates and normal feeling returns. If penicillin only has been relied upon for treatment, the abcess and pressure on the nerve can persist or return(the tooth must be removed or root canal done for healing though).