sug,
It is not unusual to feel some numbing after freezing, esp if the needle touches the nerve. Fortunately, most of the time the numbing sensation will disappear completely after a few days or weeks. In fact, the burning sensation often is a sign of healing. What I would recommend is call the dentist and inform him what is going on. Sometimes he may map the area of numbness and see how much improvement occur in a few weeks. Again, I dont think u need to worry about it too much.