I've had horrible, agonising periods where my mouth would be filled with 20+ ulcers, it was excrutiating, I couldn’t talk let alone eat :(
I tried Bonjella, the mouth-ulcer gel, and also this other stuff which is a numbing paint designed for mouth-ulcers. Both were effective but NOTHING worked like salt rinses did. I would make the salt solution as warm and as strong (salty) as possible, and hold it in my mouth as long as I could bear it. Sometimes it would even make the ulcers bleed, but it made them heal faster than anything else did; and provided temporary relief from the pain too. Hope this helps somewhat and they leave you alone soon!