Check ur humidity and try forest floor or coco substrate moistened if its too low n u havnt done so yet.
You should def get a sterolite container like 20 liters or so. Put about an inch of warm water in n let him hang out for 15 min to a hh. Should be pretty easy to get the rest off n just keep n eye on him in the future. When his go grey get one of hides super humid moist moss or moist paper towels n keep them moist for the remainder of his shed. Should be a diff result. Make sure he has something good to scratch himself on like a rough rock or branch or half log to get him started good.

These animals actually have a way of releasing water in some way to this going good or pee or something.
One time i put my ball python in a sterolite container with dry paper towels on the bottom n within a hh of cleaning his tank the sterolite container was drenched an he was almost completely out of his she a perfect shed. So its safe to say they dont need to soak his water is not even close enough for him to soak in and he obviously retained enough moisture somehow or another. His enclosure is almost always at about 65% pretty consistently since i switched from aspen to coco husk. My older male is on aspen as he wouldnt feed after changing his substrate i had to go back n his last shed was similar. His is at about 45 to 55% humidity the best i can do with aspen unfortunately. Ive found giving him a warm bath about 3 times gives him a much better shed his eye turn grey n he shed his skin anywhere from 10 days to as long as 20 days after i nitice him going into shed although idk if thats normal. He is just a nomal my male banana pastel g stripe sheds really well everytime so far but much younger, hes 2 the other is about 8 an 2 kilos so his weight could possibly be a factor too i think idk.

Also my snak had some coloration on some of his shed but all of his scales are there so i think it just takes some extra skin instead of just the top layer its supposed to shed.