i had a molar pulled last year thet was an absess and very infected and painful ,i had donated blood in the same week and the next week i came down with a bad case of flu ,about 2 weeks later i developed a canker sore on my tongue it was painful and cant rememember having one there before though i have had them my entire life after eating sugary foods it went away after a couple of weeks and then i noticed i had pink bumps on back of tongue and almost corrugated on sides with a small white patch towards the  back i became very worried as it lasted several weeks after i went to the doctor they gave me antibiotics that didnt help its been over 6 months and has seemed to get better but not completely plus have to have molar on otherside pulled am currently putting white oak on gums overnite .
Hi, Thanks for asking the query, Canker sores occur due to physical or chemical trauma. It could be an ulceration or a sort of infection. A thorough clinical examination and evaluation by the Dentist is required. Apply Hegel oral ointment topically over the affected area. At home take lukewarm saline and antiseptic mouthwash rinses. Avoid eating of hot and spicy foodstuffs. Take multivitamin supplements. Hope this helps out, Regards...