Joining Dr. Oz for his "beauty school" lesson is Harvard-trained dermatologist Dr. Susan Evans. She says people waste billions of dollars every year on skincare products and treatments that simply do not work.

Dr. Evans brought along a Visia Complexion Analysis System to get a closer look at what's going on with skin. "It actually uses ultraviolet and polarized light to look deep into the skin," she says. "It shows you things that you can't see with the visible eye [and] you can't see with a magnifying glass."

The machine takes two photos of a patient's skin. The first one is a highly magnified view of the visible skin—the epidermis—showing visible fine lines, wrinkles, pores and the brown spots and unevenness of skin damage.

The second photo goes even deeper, showing the dermis. This photo shows not what is, but will be—the indicators of sun damage that will lead to more wrinkles and brown spots in the next decade or so. "Sort of a normal progression if you've been out in the sun," Dr. Evans says.