Quitting smoking cigarettes quitters opinions needed)

Ta
I'm 23 days free from smoking, this is my third and hopefully my last time quitting, as in I won't have to have a reason to quit again. I feel so much better, I did gain some weight but my thyroid was also high again (medication was fixed) so I don't know if quitting just helped or my thyroid was the sole culprit.
Anyway, anyone who's quit smoking cigarettes, did you develope mouth sores/ulcers and if you did about how long after quitting. 
I have three mouth sores (I've gotten these before but not more than one at a time), one is healing really fas, one just barely developed but is small and one bigger one between my gums and cheek that's taking its sweet time healing. Being the hypochondriac I am, I'm terrified that one could be oral cancer so if it doesn't get better within 2 weeks starting the 11th this month, I'll be going to my doctor and/or dentist.
This is the worst one, it doesn't look bad but it's  not very nice.