Not uncommon. Sometimes you can get temporary paresthesis. Numbness from rubbing up againest a nerve while anesthetizing.. Sometimes you get a sock like feeling in the tongue from this and lip and tongue can feel numb for several days, up to several weeks. Let your dentist know if it continues.
You should read the thread under Sargenti Paste. I had a root canal done and have sinus problems ever since. I did some more research on it and read where you can have problems days or longer after the procedure is done. Formaldehyde can't be good for anyone...that is living anyways.