At the start of the battle you need to go into your cure menu. Use a syrum to heal your poisoning and use the knife, styptic and bandage to heal the crossbow wound. As for the boss itself, it's a really easy battle if you know how to play it. Select your weapon of choice, as an odd decision i chose the shotgun and found the battle took barely two minutes with it. If you can aim well and go for headshots whenever possible you can inflict some serious damage.. If he bounds off into the distance you can chase him down, or equip your sniper rifle and go for some more headshots wherever you can. Having the thermal goggles equipped for the whole battle is a good idea since not only will it help you detect all the traps, but it will allow you to see him much easier when he is camouflaged with the trees. When he says he's hungry, use that as an indication that he's vulnerable and have at him.
Stamina kill reward: Spider Camo