Good advice above on using tape or other products to keep pressure off hotspots. Tincture of benzoin can help lots of products adhere better if you have trouble getting them to stick. I am blessed with feet that don't blister easily, and have figured out which footwear systems work well for me (although I had a bad experience with a set of ill fitting zamberlans once that still makes me cringe). I still carry a little moleskin in our first aid kit, but it's more for padding or cushioning purposes and I haven't honestly used any in years. Have also had good luck using plain old band aids if applied as soon as I notice discomfort....
Can't emphasize prevention enough...got to pay attention to your feet as soon as you start feeling hotspots, and work to address the situation before an actual blister develops. In 2012, Luke and I joined a friend who had drawn a coveted sheep tag on his dream hunt. He experienced exactly the same situation Jdog described, with kenetreks stretching on him after getting wet. Our buddy figured he would just "power through" the discomfort when he felt the hotspots developing on both feet on the 18 mile hike into sheep country. By the time we set up base camp, our buddy had the worst blisters I have ever seen on his heels, and behind the toenails on both big toes. He was literally incapacitated, and we spent five days scouting sheep (some of them legal) while our buddy sat at the tent unable to walk more than a few feet. After much begging on his part, I reluctantly lanced the blisters on his toes with a sterile havelon blade to reduce the pressure enough for him to hobble the 18 miles back to the truck without ever getting to hike up the mountain.
Got to pay attention to your feet as soon as discomfort develops...while blisters aren't always avoidable, addressing hot spots right away can keep them from wrecking a hunt.