I had those darn things! At one time I had 11 (ELEVEN) in my mouth at the same time! I got them every 6-8 weeks when I quit smoking. First I blamed the commit lozenges and quit using them. Next I blamed vaping-quit vaping, still got them. Then I blamed the snus (wasn't gonna quit THAT tho!) I saw my dr about it and he referred me to my dentist. I saw my dentist about and he didn't really have any answers. Then when I went back to the dentist clinic for a followup a few weeks later his hygenist approached me and told me that she had been to a conference recently and that topic came up. What they were told is that MANY people, when they quit smoking, get canker sores off and on for quite a long time. Sometimes six months to a year. The only thing that can be done is manage the pain until they go away, which they will eventually. They were told this was just something some people go through when they quit smoking.