Warm salt gargle, ice cubes and ice chips, cold drinks (though I know for some people, it upsets their GIs), and avoiding spice and too much salt is how I deal with mouth ulcers, deep cracks in the corners of my mouth, and roof of mouth and side of tongue 'burning'.
Ibuprofen to help the pain, topical lidocaine if it's really bad (sometimes it is).
Extra B vitamins, extra calcium and magnesium (citrate, 2:1 variety) helps, too, for some reason.
I've heard that mouth ulcers can occur as a response to lowered immune and as a response to lack of certain nutrients, so I guess in my case, the extra B, calcium, and magnesium help for that reason.
But another thing to watch out for, though, is a cold sore infection (herpes simplex of the mouth; it's really common just not everyone shows outbreaks) and coxsackie virus infection.
Adults usually don't get coxsackie, but after a series of flares - each coming with a different mouth-related issue - I got a flare that led to a small blistered rash along the side of my mouth and ulcers inside my lips and in my throat and my doctor swabbed me just in case like he always does... and it turned out I had -somehow- gotten the coxsackie virus that had been going around though previously, all the other ulcerations were of the non-infectious variety.
I blamed working during holidays.
Hugs to everyone!