Caterpillar stuck in molt?

I have recently adopted a tobacco hornworm from a pet store, and I think it’s had trouble molting. The fella (lovingly named Glorb) got their face shed off but I feel that the caterpillar looks wrinkly. I also keep finding Glorb on the edge of their enclosure subtly quivering with its head tucked in and moving its mandibles as though they’re eating something. Also, I don’t know if this is normal for hornworms, but there’s never a silk pad. Like they look like they’re molting, I offer a little banana peel (I don’t have any tomatoes right now but I heard they can eat the peel) and Glorb immediately crawls onto it and starts munching. Here’s a picture of em

If this is not normal can you help a caterpillar shed or is it a matter of time at best