Greetings from healthcare magic members, I have understood the reason of your worry and concern. Teeth when infected can cause lymph nodes to swell which is a body defense mechanism to combat against various pathogenic organisms. Root canal therapy is performed when the central tissue (pulp) of tooth gets infected. The most common reasons for infection are deep cavities, poor oral hygiene, cracked tooth, failed or leaky restorations/fillings. If the infection is left untreated, it can cause gum boil or pus formation and if severe can lead to other symptoms such as fever, intense pain and abscess formation over the entire affected area. It is unfortunate that you had history of multiple root canal failures which could be because of incomplete eradication of infection by your dentist, incomplete visits or non compliance at your side, anatomical reasons or re-infection due to improper oral hygiene. Whatever the reasons were, It is now recommended that you maintain proper oral hygiene. Brush your teeth after every meal and don’t forget about flossing to clean the interdental areas which are inaccessible. Take out time to visit a good dentist and get your complete and thorough dental checkups done. Medications like antibiotics will help in solving the problem temporarily but it will not eradicate the root problem. Hence, i would recommend you to visit your dentist as soon as possible. Hope this answer is helpful. In case of any further questions, please do not hesitate to ask me Best Regards, Dr. Khoja