Hello This is ulcer on the tongue.. May be due to some sharp edges of tooth.. Due to eating hot food.

It's looking like an ulcer. It could be due to many reasons like any sharp edge on adjacent tooth or may be due to systemic reasons. Try to eat less spicy and hot food, use mouthwash, apply Dologel two to three times over it, drink a lot of water. If it doesn't heal within a week then you can consult me online or offline for better guidance and treatment options.

You're developing an ulcer under your tongue. Kindly avoiding hot and spicy diet. Try to identify the source of this ulcer, could be sharp adjacent tooth or intake of any hot or sharp food. Healing will take atleast a week's time. Kindly apply Rexidine ointment over it.