Addie3137,
The epidermis is the outer layer of the skin. It's function is too "make a skin waterproof it acts as if its a barrier, and it helps give us skin tone." Epidermis also helps us have homeostasis which is how the body keeps cool or warm. Epidermis contains sweat glands which produce sweat once the body reaches it's limit when exposed to heat, and sweating helps keep the body cool.
Hope this helps!