After extration, pain
duration depends on many things like how difficult it was, experience and skills of operator, injection techniques and accuracy of not to damage the nerves, age of the patient, underlying problems like diabetes
, blood pressure etc. The other side of pain may be associated with difficulty during extraction (traumatic) so it will take time to go. You can give him powerful painkillers like ibuprofen
400, 600 or 800 mg as required.