Hie...pain of erupting wisdom tooth is intermittent...sometimes it get aggravated during stress...there may be slight flap of soft tissue over the tooth and there is pocket formation.. food particles get lodged into that pocket..it causes localised infection in that area due to which swelling may appear..
Next Steps
If the severity of pain is high you can see a dentist and get cleaning (scaling) done in that localised area...dentist may ask you to take some antibiotics and analgesic( pain killer)for 3-5 days to control infection and pain .
Health Tips
do gargles with warm water with little salt 2-3 times a day at least for a week...while gargling hold warm water to infected side for 20-30 second and then spit it out..make sure food will not get lodged there.. make a habit of gargling after you eat anything to avoid food lodgement..