To earn a face pain that's critical to earning the platinum you MUST finish the game with a Tsuchinoko in your inventory. Once you get captured, all your gear is taken away; Eva has most of it but she will not have your animals/food. Once you make it to the waterfall and receive your gear, head back outside the waterfall and search the immediate area for the Tsuchinoko. It appears as a short, fat snake; Thermal Vision helps locate it as well. Keep it with you to the end of the game and you will be rewarded with the Infinity Face Paint.