Need help understanding

No matter how careful I am the skin just inside the mouth fails to hold and the lips peel. You can see in the picture how it starts inside the mouth. The white gunk is not just a build up of dead skin/saliva in my case, or is it ?

I am applying a 0.5% steroid cream at the moment called Emuovate to act as a barrier. I only need to apply in the afternoon and evening and it keeps the lips looking soft.

SOmetimes I wonder if there isn't the top few layers of epidermis missing inside my whole mouth, from biting it off and that maybe if I didn't eat anything for a few days, just water, it would cure my EC.

It's so hard to apply anything all the way around the inside of the mouth because there's nothing that doesn't taste disgusting.

Any feedback ?