Don't go buying trouble, Salvo. The canker sore is probably exactly that. Although I didn't experience that particular side effect, many others have. I am not a doctor, but it seems to me that your body is busy healing and the sores are a result. Keep track of it for sure, but don't loose too much sleep.
I am three weeks into my second serious effort to put her to the curb in about 30 years. This time I only have one sore in my mouth , but about two years ago there were sores everywhere. It SUCKED! It also went away after about a week.
Couple of observatons....first of all, it is probably nothing expect your body getting used to being without one of the 4000 chemicals that it has been used to. Secondly, it could be something that you are using as a substitute (are you eating too much citrus? getting splinters from tooth picks? Other??). Finally - if you are worried, buck up and call your dentist for a 10 minute checkup. I never missed a six month appt with mine and he always checked me for cancer....tell him what you want and offer him $20 under the table.
Hang in there, and don't let the stress trick you into doing something that will result in another dead kitten...regardless of what is going on you are better off without that goose shit in your mouth.
I've always went to the dentist regularly as well, but never admitted that I chewed until last year. My dentist is a 65 year old very conservative guy. So I tell him that i have chewed for 20+ years. To my amazement, he tells me that he had a 30+ year cope habit. Says he used to train horses and got hooked on cope while hanging out at the track while in college. He checks me out and says everything is ok and tells me what to look for in the future. Then he says "It probably wouldn't be a bad idea to try to quit". Not quite the scary lecture I was expecting.