Hi August,
Sores in the mouth that are commonly called "apthous ulcers", are caused by a virus. They will usually go away in 10 days to 2 weeks. They appear as small white craters, with a reddish border and can appear as a single ulcer or in groups. They will appear more commonly when a person is run down and their resistance is low.
I don't agree that constant irritation is not a possible cause of scc. This is not my opinion alone. I have discussed this with the Chairman of the Department of Otolaryngology and Head of Neck Surgery and Immunobiology at Mount Sinai School of Medicine in New York. He referred me to
www.pubmed.com Jerry