I have a scar on my wrist (surgery) that is thin like that because the skin there is thin. I see the “micro tube” you are talking about, but it could possibly be a scar.

The reddish brown plastic looking thingy looks medical to me and I’m thinking it’s a PICC line port, a line clip or extension (for easy sleeve access?) I’m not a medical professional though, and I can’t seem to find a brand/size/color that looks exactly like that online.