An x ray will confirm if the swelling is related to an infection in the same root canal treated tooth. Root canals are successful in most cases but some infections are very resistant and do not clear despite the most sincere efforts by the doctor and the patient. In such cases an small surgical procedure can be attempted or a re root canal can be attempted before deciding to extract the tooth since you are young patient and the it's a front tooth.

Please visit the dentist again..And tell him about this. He will look into it...Cure can be given only if we ascertain the cause.

U need to get an X-ray done to know the status of the root canal treatment nd if everything is fine Localised cleaning around the concerned tooth followed by warm saline rinses nd massage will be helpful..