I upgraded from an S8 to a U2 on launch and have been wearing it since. I recently noticed a red area on my wrist directly under the sensors. It doesn’t hurt, burn, or itch. My skin isn’t raised and feels normal to the touch. If you look closely the skin is “scaley” (and red, of course). Anybody else notice this?
I have something like this also, but on me it looks more like a tan. I wonder if the green light these produce causes some melanin to migrate to that location in some people.