The pit does not have any magical properties. What turns the guac brown is the air. If you can keep air from touching the guac then it will stay green. The pit will keep a portion away from the air, but what is more affective is to put plastic wrap over it and push it right down onto the surface.
Denuded skin is just another way of saying that the top layer (epidermis) of skin is gone...either from friction (abrasion or tear), trauma (tape burns), or severe rashes, or from a stage II pressure ulcer.
Pressure Ulcers. A pressure ulcer - also known as a 'bed sore', 'pressure sore' and 'decubitus ulcer' - is an ulcerated area of skin caused by irritation and continuous pressure on part of your body. Pressure ulcers are more common over places where your bones are close to your skin (bony prominences) such as your heels, the lower part of your back and your bottom.