I had 2 dental procedures a week apart,this last one i was numbed on the upper area above the k9 tooth. i now have a knot and a purple looking type bruise? it's very sore and causing me pain. any idea what it could be?

Hematoma: This is most likely a hematoma at the site of the injection. It should heal relatively quickly.

TRAUMA OR INFECTED: Without seeing it, it is hard to tell. Commonly, bruise is as a result of anesthetic when a blood vessel happens to be where the needle was. Then some bruising occur. This may be quite painful for a few days, but it will heal eventually. If the tooth had a bad kind of bacteria however, the tooth and gums can be infected more acutely during dental treatment. See your dentist to have it checked.