I thought the blue and mottled appearance was a clear sign of venous TOS, a situation where blood can flow into the arm, but a compressed vein keeps it from being able to flow out again.

see this link, I can't find exactly what I am looking for, but this is similar, and I don't have time to keep looking. here

Be careful...perhaps put a call in to your doctor if you haven't had the blue color before.

Have a good evening everyone-
Johanna