Question

many times you cannot eat hot food due to inflammation/ulceration in mouth.

Answer 1

Because the salt present in food or sugar present in food get attached to that area (where ulceration or inflammation occurs )and in hot food it get attached faster because of its rawness and salt or sugar make an irritation in that area so the person is unable to eat that hot food.

Answer 2

Because ulcers contain exposed ends of nerves which are sensitive to hot or cold food. These foods excessively stimulate the nerves which causes pain and hence the person cannot have such food.