Sun spots form when skin suffer sun damage and the amount of melanin increases. The spots have uniformed edges and can be brown or gray in color.
There are over-the-counter medications that can be used to lighten the darkness of the sun spots. These products stop the production of melanin in the skin, which keeps the spots from darkening. If the sun spots start to change in size or color, see a dermatologist right away. Changes in sun spots can be an indication of skin cancer and must be addressed immediately to obtain any necessary treatment as soon as possible.