On a tablet so I can't see exactly what it is.
It could be a piece or stuck shed or he may be starting the shed. Either way boost your humidity to help him out.
A very easy way to provide good humidity is by placing moist moss in the hides. This creates humid hides and since you're snake will spend most of its time in the hide the humidity is used well instead of trying to keep the entire cage higher. Moss will also offer a feeling of more security by closing any gaps in the hide because they like them snug. This is also a good tip when you have to use a hide that is a bit to large for a snake. It just makes it feel smaller.
If you don't have moss right now boost the humidity by misting the cage a few times a day.