I burnt the roof of my mouth with hot food, and there is a blister. how do i treat this? also could this get infected?

It will heal: Although it is painful at times but it would heal by itself. Take it easy and you can apply otc toothache cream. It will take the pain away till it heals in a few days. Good luck.

Cold water: If the blister pops, or if there is a break in the surface, there is always a chance of infection. The best thing to do with a burn (*anywhere on the body*) is to apply ice or cold water to it IMMEDIATELY. Don't wait - the sooner you apply cold, the less damage there will be. Yes, it'll heal with time, but there's still time to gargle & swish cold water/ice slurry now, as long as you have symptoms