What Causes Canker Sores On The Lips While Suffering From Grave S Disease?

I have had canker sores twice on the lower inside lip. I have Myasthenia Gravis & Grave s Disease along with Von Willebrandts Disease. I went through two surgeries for fecal incontinence; the first, was a sacral neurostimulator interstim & met the criteria for it to be permanently implanted. Feb. 28th for the test to see if it would help; the permanent implant March 10th. My mouth has had canker sores after both procedures. My lower lip is covered with small red patches & blisters. I went to my dentist & she prescribed Triamcin/OraBas 0.1% Dent-Past 5GM at bedtime. My body has been through a lot and my skin is very sensitive to many things. I am allergic to Macrobid, Diflucan, Flagyl & Iodine (IVP Dye). I am a smoker. My surgeon kept me off work 2 weeks longer for me to heal at the incision site & due to the work I do which requires me to lift, bend, on my feet 10hrs a day. He feels my Autoimmune System has been weakened. Yes, I know smoking is bad. I need to quit & will get help with this. Do you think this medicine will help? I appreciate your time in reading my issue{s}. Thank you very much! Do you think as I do my autoimmune issues & all are what have caused the flare up with the canker sores.