Had one last week used cheap gel called medijel it soothes the sting instantly and went in 2 days. Dollar stores and poundstores usually have mouth ulcer gels. They work well.
They're like the worst thing ever
Is something that happens to me like 3-4 times a year... but it's because I always bite my nails and I always get hurt in the gum, it's a horrible habit that I need to leave