Tooth pain with swelling is usually due to a dental infection or gum problem, where bacteria cause pain and fluid buildup. Rinse your mouth with warm saltwater, keep the area clean, and avoid very hot, cold, or sugary foods, as they can worsen pain. You can take basic pain relief if needed and apply a cold compress on the outside to reduce swelling. As swelling is present, it is important to visit a doctor or dentist soon so the cause can be treated properly and prevent it from getting worse.