Lurker here but I've got a home remedy that works as well or better than the prescription medicine I used to put on my mouth ulcers:

1 teaspoon salt
2 (generous) teaspoons hydrogen peroxide
a few ounces of very warm water to dissolve the salt

Mix well, swish in mouth trying to keep the solution on the sore spots as long as possible.

I got that recipe from a periodontal surgeon after having gum surgery years ago and it works wonderfully for mouth ulcers too. Within a couple of days they start to heal up. Good luck, those are so painful.

I've used baking soda -- just a little dab straight on the sore. Hurts like the dickens for a few seconds, then no more pain, period.

Lidocaine spray (over the counter) - do not swallow.

or

Hydrogen Peroxide, dilute with ginger ale or 7 up (swish around the mouth).

If it's very bad, Decadron rinse (PX only).

I tend to get those a lot, mostly from biting the inside of my mouth or tongue. The best thing I've found is zilactin, which is available over the counter at drugstores, typically by the lip balms and such. Apply as soon as you suspect one is forming, and if you bite your lip, apply it immediately. Apply 3-4 times a day, and they'll heal up in about a week. If you wait too long it takes longer to heal. Without the zilactin it used to take about 3-4 weeks for them to heal for me.

Make sure you get the "regular" zilactin, which has alcohol, and not one of the variants which only contain a painkiller. My personal theory is that the ulcer is basically an infection, and the alcohol acts as a disinfectant/antibiotic to stop the infection.

There's also a possible link between the foaming ingredient in toothpastes and canker sores / mouth ulcers. I think it's laurel sulfate or something like that. I switched to a non-foaming toothpaste for several years (Closys) and did notice that my canker sores decreased quite a bit. But unfortunately Closys doesn't have fluoride and I got some cavities so I switched back to a "regular" toothpaste. You may want to try the Closys until your reno is over (it's available at Walgreens).

tip tap tip tap....
that's the sounds of me running to find that baking soda then searching for salt and hydrogen peroxide... ingredients!

Thanks
Em

I usually put a little hydrocortisone cream on them. While it's not generally for oral use, the small amount you use will not hurt you.

I used to use hydrogen peroxide and then used Baking Soda but found that just swishing a good mouthwash several times a day really helps me.

Good luck.

If it's canker sores, an old remedy that works is rinsing your mouth with cultured buttermilk, or applying a bit if it directly to the sore. I read this somewhere in a medical column in a newspaper. One of those old cures that actually works...something about the bacteria in the buttermilk being beneficial.

I grind my teeth at night also, and get sores on my tongue as well. My dentist told me it's all stress related. and there is a medical term for the tongue sores, but I can't remember exactly what it is.