Lump under lip with numbness

I had a temporary filling put in to avoid a root canal that was caused by a regular filling gone bad. The tooth is the first one on the right side of my front two teeth. The dentist worked me in as an emergency because I was in so much pain. In the course of the four hours I sat there in between patients I was given several shots of novacaine ( I guess because it was wearing off) anyway, I haven't had any pain but I felt a numbness and tingling every since when I touch the outside of my lip underneath my right nostril. I asked my dentist about it but he said it was unrelated. I didnt think so. Now I have a knot on the inside of my lip and its hard to the touch from the outside. I still feel the numb sensation when I touch it. Im worried. Please help.