We've been told by a previous zoo employee who has now opened his own practice that until the mouse moves further down, he won't be able to close his mouth. He says not to worry, snake is just eating it more slowly but if he's still like that in the morning and the mouse hasn't moved down at all, then to give him a call.
Snake will likely be OK he's just taking his time eating. He has been active and doesn't seem to be panicking or stressed at all.
Have just misted the terrarium I bit
Thank you both <3