35 gallons is too big for an animal that size I would recommend you to downsize to a 10 gallons tank or even better a 15 quarts tub.
Security is very important even more so with young individuals.
You need to provide 2 tight and identical hides so your BP can thermo regulate and feel secure.
The hides must be snugs will all side touching your BP's body
Until your BP eats with consistency, no more handling.
Move your BP in a new enclosure providing optimal husbandry and leave him alone (NO handling for a week).
Once a week has passed offer a live mouse and see how it goes.
If your BP eats I would still recommend to limit your handling (2 to 3 time a week) until, your animal is consistent.
Once your BP is consistent and well established you can try to switch to F/T.
And remember force-feeding is not the solution at this point.