What Do Small Brown Flakes Of Pigmentation On Palms And Fingers Suggest?

Hi. Lately I have been finding small brown flecks of pigmentation on the palm-side of both hands, including the fingers. They do not disrupt the texture of the skin. they almost look like diffuse scabs under the skin. This started being noticeable in the past 3-4 months. They each individually appear, and then each individually disappear after a few days as the skin wears off naturally (they are in the very top layers of my skin, it seems). There is no itching or soreness, and no redness. I m concerned because I work in a materials research lab. I m 30, male, Caucasian, in generally good health, and I work out regularly. Nothing in my workout has changed substantially enough that I would think this is from lifting the weights at the gym. Any ideas?