Firstly, has the dog been vaccinated?
Secondly, have you taken anti tetanus
injections and antibiotic for the wound?
pain in the site of the bite signifies possible delayed healing due to uncontrolled infection or a too deep laceration that would take time to completely heal.
Pain relievers may help but if the wound is still open or not healed, you may consult a nearby hospital for dressing and further evaluation of the wound.