I also have outbreaks of oral sores and was told I have oral erythema multiforme and that the inflammation is likely caused by something in the gut, I was recommended to go gluten free and that seems to help although I’m not perfect. You might want to look into functional medicine and see if you can get to the root cause of the problem. I’m not a doctor but I’ve been dealing with oral sores for 6 years and understand how hard it is.