Unlikely to be a sexually transmitted infection, if that is what you mean by STI.
Could be infection though, viral
or yeast but yeast would usually be a white tongue.
The most common condition that leaves raw looking patches on the tongue is graphic or geographic tongue, which in most cases has an unknown cause, although some see links with nutrition, particularly B vitamins.
For unknown reasons, the tongue in this case sheds unevenly, leaving the bare patches.
Other potential problems are dental causes so if you have not had a recent dental exam then you should. An acidic environment, even sour candy, can cause tongue peeling.
Since this comes and goes, it is almost assuredly a benign condition.
But have someone look at it.
Please click accept to give answer credit. Positive feedback highly appreciated. Bonuses helpful. Answers for informational purposes only.