I applied garlic poultice w/ coconut oil/guaze to arches/soles of feet for a few days and slept overnight-large pieces of skin on arches peeling-why?

Sounds like. your feet got macerated, or to moist. If you left the garlic poultice and coconut oil on your feet for long periods of time the feet got to wet and the skin peeled. Leave the poultice off for a few days and if you have loose skin don't pull it trim it with fingernail clippers so you don't get into attached skin and cause more pain. Are you trying to detox or something, nvr heard of that combo.