I initially got chronic canker sores (aphthous ulcers) from Rapamycin. They came and went for many months before I found the cause and a really helpful treatment.
I have had my canker sores under good control for the last six months, after suffering badly for about nine months. The sources of my treatments comes from a lot of trial and error research and suggestions from various pundits, including Dr Peter Attia.
The biggest breakthrough was when I changed from the major brand toothpastes, which mostly use an ingredient called sodium lauryl sulphate (SLS). SLS is a surfactant also used in household soaps and detergents. It creates a bubbly foamy effect. It seems totally superficial but apparently makes your teeth āfeelā cleaner. SLS is rated as a high hazard for mouth irritation and a moderate irritation for your organs.
Go figure why itās allowed in toothpaste! Since I changed toothpastes, Iāve had only minor irritations. And none of the āalmost comic painā described by Peter Attia when he had canker sores.
Learned dentists recommend not using toothpastes with SLS if you are sensitive to any form of mouth sore. Itās superfluous to good dental hygiene.
SLS is absent in Dr Bronners and Sensodyne toothpastes. I prefer the former as itās also absent fluoride - i think we get enough of this as an additive in drinking water and dental cleaning.
Hereās a link to Dr Bronnerās peppermint toothpaste. Peter Attia also recommend Dr Bronnerās. Sensodyne is ok if you want the fluoride.
The producers of Blistex have a useful product called Kanka. I found that this helps with established canker sores. It reduces the inflammation and deadens the pain to help you avoid irritating it further when eating. Some of my early canker sores lasted 14 miserable days.
For completeness, these treatments did not work for me: red light devices, alum powder, saltwater rinses, baking powder, honey, Hydrogen peroxide, coconut oil or Milk of magnesia.
I hope that most of you can find the same relief as I have from these treatments and by discarding toothpastes with SLS.
Good luck.