Ball python crease/line down belly

[Homebody]

I'm worried this could be the start of scale rot. If anyone has any advice it'd greatly appreciate it. Thanks

I don't think it's scale rot. Scale rot is caused by damp dirty substrate. Unless your substrate is damp and dirty, I don't think you need to worry about scale rot. That crease is curious though. I'll be interested in learning what other have to say.