Your hands did not fall off after 500 trees in one season? Come on, that is a lot of cutting and hauling and dragging. I have done maybe a couple hundred in a good year and my grip was toast for a week. Either you have forearms of steel or you are leaving out the part where you soaked them in ice every night. In my experience the tendons are the first thing to go, not the skin, so take care of those before they get mad at you.