Just monitor it. You'll know more after it sheds. But also rectifiy the problem if you can find it. A vet can't really do much for you, except tell you to pump it full of anti-biotics that it deosn't really need. A snake can heal from even the worst case of scale rot without the help off anti-biotics and ointments.
You say you use artificial grass. Well, unfortunately, that stuff harbours a lot of bacteria if not washed regularly. So if your snake spends a lot of time sitting on it, then chances are it's getting bacteria under the belly scales. A lot of times when someones snake gets scale rot, they are keeping it on artificial grass. For now, I recommend newspaper and a warm surface, and also keep the water bowl away from heat sources.
Also, it's important to point out that snakes can burn/damage themselves much more easily during their milky stage of shedding, if they spend a lot of time sitting on a warm surface. They are quite insensitive to heat on their bellies. The heat tends to dry out the shedding oils pre-maturely, and when they shed they end up pulling the new layer of skin off with the old. This can lead to significant scarring.