With the terrain of mud, water, roots, rocks, climbs, drop-offs, and then more mud, water, .... keeping your feet in good shape is key to finishing and doing well at the HURT 100 Mile Trail Race.
Over the years, I've picked up tips from various runners. For a wet race, I stick with what Rob Edde told me about what Blake Wood recommended for Hardrock - Baby Diaper Rash Ointment (zinc oxide). Since I've used it three years ago, I haven't had so much as a blister due to maceration or water. Coupled with Injinji socks to keep my toes from fighting, and a thin cover sock, I'm confident my feet will do well at HURT.
Of course your feet may vary.