It is a form of glossitis. The patch is expected to persist for some weeks,, might heal and recurr at different part of the tongue. Most common cause is
vitamin and mineral deficiency,
B12 being top on the list.
Next Steps
Star with multivitamins (containing Vit
B12, Iron and Zinc). Get a dental consult too for the upper incisor and make sure that u are not in habit of subconsciously feeling your tongue at this spot with that tooth.
Health Tips
A physical consult will help ruling out other causes.