Marks from back of iwatch

So, for about a year, if not longer, i thought something was biting me in the exact same spot but randomly. I was racking my brain trying to figure out what i was doing, where i was, where was the pesky bug that would just randomly bite me. It wasn't until today that a coworker said maybe it's your watch...and then it wasn't until I took the watch off and noticed that the 4 silver/clear dots on the back of my watch matched up identically. i called support and they have made an appointment for me to get the watch serviced. I keep seeing comments about "allergic reaction" but this can't be the case since i wear my watch everyday, but don't have these marks everyday. Also, i wear my watch loosely-on the last hole since i don't like it too tight on my wrist. Just curious, has apple noticed any issues? I really like my watch and unfortunately, not sure if i can wear an iwatch after what it is doing to my skin.