Skin Rash

I noticed a rash on the underside of my forearm today. I was wondering if anyone could tell me what it is. The rash consists of many small greenish-grey dots. They are not itchy or raised. I am a little under the weather, but that is attributed to seasonal allergies. Have any of ya'll ever seen a rash of this type. If so, what the heck is it? Thanks for your help.