Blotches on palms

In various occasions now I have woken up to find the palm of my left hand with brownish blotches under the skin.  There is no pain or itchiness and even looks as if it's on the surface so I instinctly wash and wash my hands but it's still there.  The blotches disappear throughout the day but when I least expect it, I wake up again to the same situation.  Sometimes there are just a few, but today I woke to find there are many more  and even on the fingers (bottom palm area) and more evenly spread like.  It doesn't hurt but it's scarey.  What could this be??