All a complete waste of time so don't bother.
I have suffered from mouth ulcers on and off for many years. I have consulted my GP, my dentist, a number of so-called specialists and various "quacks". All agree that nobody knows what causes them and none of them can recommend an effective cure (even the "quacks").
I have my own cure. A large shot of Remy Martin, liberally applied to the infected area. It is absolutely crippling but cuts down the period of infection by about 50%. As a recompense it tastes quite nice as it goes down and numbs the pain.