There are hundreds of other oral conditions that can be the cause. I think with CHC, the ulcer does not go away or can ge rubbed off, but there are many types if cadidiasis too. It's best to see the doctor with anything not going away in three weeks, to be diagnosed properly, and receive proper meds, if needed since one does not work on all. If it's an event type ulceration from food, drink, it can be from spices, sharp edged, cruncy foods, and irritant like alcohol. Salted warm water with baking soda, is always a good standby. if it burns, just use baking soda. I hope this helps.

Maybe take a picture if you can, before it disappears, to show the doctor.