Don't worry ,mostly this is reversible and does take care of itself within a couple of months .
It is due to accidental nerve injury during the injecting of the local anesthesia ,though not common but can occur with even a single injection and not necessarily due to multiple injections .
Just bad luck that it happened ,but take solace in the thought that it is reversible and you should be fine in some time .
Neural vitamins like the ones suggested above will help regenerate / heal the nerve fast ...
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