Two regurgitations spanning a course of less than 3 weeks should not have made a snake emaciated (I figure that is what you mean when you say hollow). When you say hollow do you mean its like his skin is to big on him? One "Juvie" rat every two weeks? Need to up the frequency on that a bit go with once a week.
As far as temps I would kill for your ambient temps, you still might need a small heater to keep the room warm enough at night (If you are using room heat aim to keep it in the mid 80s (I like 86))