It could be a fungus. I used to get that because i worked out with my shirt off, so the sweat produced it. For me it was little dark spots on my skin. The dermatologist. gave me this topical suspension to get it off and it worked.
so your seein spots? well you should describe a little more detail. where are they, color, shade, how long, have you done somthing differently recently? you get the idea. probably is fungis though.