Finger turning blue?

I noticed my index finger had a blue/black mark on it weeks ago. At first I thought nothing of it and thought it was prolly just ink smeared and would wash off... a couple weeks went by and still there so I thought maybe it’s a bruise. But it doesn’t hurt and still another week went by and no change! Any idea what it is? I’m a little over 18 weeks prego.

U might be able to see in the pics that my middle finger on the same hand has a little strip of the same thing and it kinda looks like it’s where the vein is