On rare occasions, an injection of local anasthetic can have lasting effects. I'm guessing that the tooth that was fixed was a lower molar or bicuspid. Call your dentist and let them know, but realize that it might last for a few months more. Sometimes the lasting anesthesia goes away by itself, sometimes, very rarely, it is permanent. Nobody really knows why it happens, and nobody really knows how to fix it. It isn't anything the dentist did wrong, it just happens. It is very rare, and in most cases, goes away or gets better with time. Some oral surgeons are specialists with these cases, and will measure your progress over time. But nobody has been able to show that a surgery is helpful. So try to avoid that. The current theory is that a rare reaction with the anesthetic (somewhat like an alergic reaction) causes the nerve to demylenate, causing pain or lasting tingles. But again, nobody has proven that and don't really know if it is true. Your dentist will probably tell you to wait it out, and is probably right.
Then again, it could be something completely different. Like the fracture was more serious than thought, and damaged the nerve, although I can't see how. Could be that the needle actually penetrated the lingual nerve (rare) and the nerve has to heal itself. Can't really tell without more investigation. You should get some help with this one if it continues. Hopefully this is just temporary.
Good luck. I hope all turns out well for you.
Many thanks for the reply - very interesting. I am hoping it is temporary, but it is not showing any signs of improvement at the moment. It was a lower molar that was crowned, and when I went back 2 weeks later for the permanent crown I did mention the complaint to my dentist, who just said that he could have bruised my tongue with the work that he did! I am seeing him in 2 weeks time for a check up so will mention it again if it is still troublesome.
I am now also wondering if there is a link between anaesthetic, any anti-biotic and candida & will be investigating that further!