You look around for some herbs and honey that you can mix together before going on. You consume the mixture, which quickly heals many of your wounds. Next, you slay a small animal for its meat; you're going to need your energy. You cook the meat, eat, and finally follow the trail left by your paintball.
When you reach the monster, you see it has fallen asleep in its den. It's perfectly prone now; although you probably still can't end it with a coup de grace, you can set up your attack however you like to ensure vitory from here.