It's important to clean-up and cover-up each night. As others have mentioned, wash away sweat, sunscreen and whatever, especially the head. I wear long-sleeve, full-leg silk pajamas. Clean socks. I recently acquired a food-service hair-net, to cover up my hair inside my down hood (or mummy bag hood, whichever you use). It's a thin, breathable material, not actually netting. I have used it just once and it works fine. It doesn't add warmth to the hood, like a beanie would.