Just a few other thoughts on what you've asked, Clara:
When a snake pushes their head or face against things, it's usually in an effort to remove old skin that failed to shed. Are you SURE his previous shed was complete?
Skin often gets stuck on their chin/neck...also eye-caps can be a serious problem if left behind. I've known MANY snakes for many years, none that sought to be pet, especially on the head & face...so that's a clue. (Some snakes, like rosy boas, will push their faces into you, but that's testing to "see where the head
is to grab for dinner", just as they do on a rodent before they pick it up.Some of them tend to be rather "confused" or very "optimistic".
)
I am wondering how often you handle him? and how often he defecates? & what is the character of the stool? You might want to get a stool sample* checked out by
your vet, as it's possible that the frequency is not normal, but instead is related to a gastrointestinal issue. *It seems you'll have no problem obtaining a sample either.
Having a BP or most any kind of snake defecate on you reliably is NOT normal. Also, feces & musk are usually rather distinct...very rare for a BP to musk. Do keep in mind though that for an inactive snake, handling, ie. motion, does tend to stimulate their defecation somewhat.
You mention that he is "hesitant" around food...it's possible that you are handling excessively & reducing his desire to eat. It's hard to tell if a snake is stressed, but one
indication is that they have a poor appetite. No matter how much you love to handle a snake, eating is "job #1" for the sake of their health. Those of us who enjoy more
snake-handling often find it's more practical to keep multiple snakes...that way we aren't without one to handle when they are in shed, digesting or just not in the mood.