I hurt my wrist and it was similar to this. the pain will get worse. You need to ice and take AIs and rest.
While you are doing this, you need to make %100 sure you are not wristing the serve. Make sure your palm is waving to the side fence in trophy pose and turning 180 degrees so you are "combing your hair" when you swing to contact.
Please help TT Member BruceD get a wheelchair so he can play tennis again - http://tt.tennis-warehouse.com/showthread.php?t=496820