That sucks, but don't take it personally! Even though your hand was on the other end of the vive, the smell of food was in the air. The chewing definitely speaks volumes to me, as a feeding response.
I would be more concerned with the snake than myself, as hog nose venom is typically harmless (of course in very rare cases it can have adverse affects, as you've mentioned that one particular case). Be careful pulling any snakes off when they bite, as you don't want to pull out their teeth and potentially cause infection - although I'm sure you're already aware of this.

Next tome try running the snake under some room temp water. Might allow the snake to release on its own if the teeth are not sunken so deep as to need further assistance.