It is possible it is from the local anesthesia. It is possible that the injection was very close to the nerve and it was traumatized. In all likelyhood the feeling will return. How long is hard to say.
did you hace it since your last visit?? it sounds like a paresthesia from the injection-- ie damage to the nerve from the needle-- it happens sometimes, and usually goes away--- but it can take months in some cases.
It started after the root canal. It just feels like the numbness wont wear off
it sounds to me like a nerve paresthesia- the nerve that innervates the affected teeth and lip was probably traumatized by the needle--- it should resolve but may take time. see your dentist to confirm it.