Hi Dear, Welcome to HCM. Understanding your concern. As per your query you had tooth cavity in right upper side which is increasing in size and swelling is also there , I would suggest you to take antibiotics first such as combination of Ibuprofen and Diclofenac to subside infection. Maintain proper oral hygiene by brushing and flossing daily. Do warm saline gargles as well. Visit dentist as it seems your infection has progressed to pulpal level. There can be many treatment options for dentist depending upon the condition of the tooth. Dentist may order X-ray before deciding the treatment option.If the cavity is shallow then he/she may fill it with composite or silver filling after removing the infected tissue.If cavity is deep ,but do not reach the pulp dentist may fill cavity with composite and silver filling after removing infected tissue ,but in this case he/she may apply liner or base before filling to prevent post filling senstivity.If infection has already reached the pulp then root canal should be performed by removing the pulp and fill it with gutta percha and then give crown on it. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari