I can actually answer this! What makes your skin pliable is a protein called collagen. It actually takes a lot to break skin or bone, so I’m pretty sure that the first thing to snap would be your tendons (flexor digitorum) because of how thick and tightly it is attached to the finger bones. In your foot, it would take a lot more force to damage the skin since it is thick skin and layered differently. So again, I’m thinking you’d tear a ligament or tendon before either snaps.
The reason why tears in the skin don’t widen over the day are again a result of filamentous proteins that hold the skin together (elastin, collagen, and also keratohyaline), plus swelling in the area is the body’s attempt at stabilizing the wound so it won’t be too exposed. Finally, you cannot roll skin in your foot, or any other place for the matter; skin is taut and the thick skin on your soles is comprised of different layers of tissue, plus an added 5-7 extra layers of dense, outer tissue to protect your feet.