Wisdom teeth start coming out around 18 yrs of age. Yours either does not have enough space or is not pointing in the right direction to come out completely. This causes food to get stuck there and infect that whole area.
Visit a dentist get your x rays done and your dentist will guide you to the best option.
Next Steps
visit a dentist. keep area clean and do warm water salt gargles multiple times a day.
Health Tips
try to find the solution before you conceive as no extraction can be done in the first trimester