Three quick things:
- Your cool side is too cold - raise it up a few degrees if you can so it doesn't drop below 76 (78 preferred).
- Not a good idea to bring your snake to a reptile show - too many possibilities for a healthy snake to end up unhealthy from its interactions at the show.
- Snakes hiss - it's kind of their thing. No need to worry at all. Think of it like you would think of a person sighing - they're not thrilled about something, but they're not upset enough to do anything about it.
Hope these help!