Skin

"The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, and cold.
Skin has three layers: The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone.
The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands.
The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.
The skin’s color is created by special cells called melanocytes, which produce the pigment melanin. Melanocytes are located in the epidermis."

Chickenpox

Chickenpox (varicella) was once considered a rite of passage for most children. Before routine chickenpox vaccination, virtually everyone had been infected by the time they reached adulthood, sometimes with serious complications. Today, the number of cases and hospitalizations is down dramatically. However, when chickenpox does occur, it's highly contagious among people who aren't immune. Most people think of chickenpox as a mild disease — and, for most, it is. Unfortunately, there's no way to know who will develop a severe case.