Have you checked out these threads here? Might this be what's going on with your snake? (I hope not but you need to find answers.)
https://ball-pythons.net/forums/show...les-Just-Split
https://ball-pythons.net/forums/show...I-RIP-his-skin
https://ball-pythons.net/forums/show...t-Snake-Owners
In case the vet you saw or spoke to isn't familiar with this, you might need to see a different vet- https://arav.site-ym.com/search/custom.asp?id=3661