What reason would you have swelling in your face for months after a root canal?

Swelling in the face persisting for months after a root canal may indicate an unresolved infection, such as an abscess or peri-radicular disease, that hasn't been adequately treated. It could also be a result of an allergic reaction to materials used during the procedure or an issue with the healing process. Additionally, if the tooth was not properly sealed, bacteria could continue to cause inflammation. It's essential to consult a dentist for a thorough evaluation and appropriate treatment.