Hi!
I think the reason you are still numb is that you were given a big amount of anesthetic. I've had the same problem myself. Had to have 5 shots of novocaine when I had a root canal done. I doubt if this has anything to do with MS, but who knows?
Ultimately everything gets back to normal, for better or worse.
ess
What you describe is what often happens to me. I have learned through the years that the nerves in my mouth are not located in the typical places, or run in the usual pattern.
They can shoot me up with all kinds of anesthesia but it does nothing unless they guess and find where they are located. I usually end up deadened for at least a day or two. I don't know if nerves can be damaged by too much poking around and medication.
This unusual path of nerves in the jaw/mouth is found in other family members.
If injections don't work insist they use gas. If they won't then go to a dentist who will.