Pop mouth ulcer or leave alone?
Ulcer or blister?
An ulcer would be described as a crater. This is best treated with 50% mixture of water and hydrogen peroxide rinses for 2 minutes 3x per day.
A blister is fluid filled.Rinse with 1/2 tsp of salt in 5 oz cup of water for 2 minutes 3 x per day do not pop.