I had my lower left first molar surgically extracted yesterday. It has been a day and a half since the extraction and I still have no feeling on the left side of my tongue. I can feel pressure but I can't feel hot and cold, etc... Its like the novacane never wore off.
There is a nerve that runs along your lower jaw bone and as they were putting the anesthetic in the area they might of hit the nerve and that would have gotten your tongue numb. Know, it can last for a few days or even years, so if i were you I would call the office where you had gotten it done at and tell the dentist about the numbness you are experiencing so he can check it out for you.