Oral ulcers come and go, why is it such a troublesome word?

(picture from the Internet)

There are many friends in life who will have oral ulcers at any time: getting angry, staying up late, burning, accidentally biting their mouth when eating… Oral ulcers always come and go, and it is difficult to heal, but every time It won’t be long before it makes a comeback. Mouth ulcers are not only painful and upsetting, but even more worrying—

Repeated oral ulcers, will they not become cancerous?