Stupid Hinox Battle

just spent 15 minutes trying to kill the stupid thing (my first boss(?) battle) and finally got it to fall and then like an idiot sat by the fire till morning because i didn’t want to get jumped by some creatures after my painful victory. AND IT RESET! didn’t even get the treasure. gonna fight the freak again but can someone Please tell me how to get the treasure so i don’t have to endure this all again