I noticed a round red spot on tongue. 1/3 of an inch, flat, seems like the skin is peeled off. it was fading but 2day i had oranges now it's red again?

Oral surgeon: Hard to say without exam. The oral mucosa heals rapidly after insult or trauma. It lesion persists after another week, see an oral surgeon or ENT doc for evaluation.

Red spot: It could be a number of things, some of which require treatment while others are benign. It cannot be diagnosed over the internet without at least a photo. Merely listing possibilities would be of no help to you. Have your own dentist or an Oral Surgeon look at it when present for a definitive diagnosis.