Lym disease can induce tooth pain from cavities or other dental problems, which can be the symptom of such disease. Usually, oral symptoms will go away after proper medication, however, the abscess in your case has worsened even after the treatment. Oral bacterial infections, such as
tooth abscesses and oral fungal infections, are more common in those with immune deficiency. Your mouth is infected frequently so I agree with you that a root canal should be performed right away. Antibiotics may be given to cure the infection, but if the abscess is caused by a dying nerve, the dentist may prescribe the root canal procedure.