You was almost there! Feeding day was coming up and you returned your bp back to the main tank? /facepalm.
He may dehydrated because he ate nothing for weeks. Getting him to eat will help him gain some weight and some liquid in him. Mine looked that way too when he refused to eat for me.
Stuck shed does not mean you need to step in right away. Give him 24 hours to remove as much as he can on his own and raise the humidity. An already stressed out snake don't need to be soaked and poked at. Some snakes will eat during shed. And don't use your fingers to peel the skin off. The stuck shed should slide right off after soaking. I sometimes use the shed ease solution mixed with warm water and it helps.
Once your set up is fixed correctly, then try feeding again.