What can be done for facial paralysis and numbness after root canal!?

Hard to say: This question is best answered by a specialist who can see you, take a medical history, and discuss exactly what went on before, during, and after your treatment for this tooth. Too many variables to be answered intelligently over the internet.

This is unusal: Not only unusual, but concerning. Be evaluated by an endodontist or oral surgeon. Ask your dentist to refer you to a provider he trusts. The sooner the better.