My Mom had eczema really bad years ago like I've had these past few years. I would put money on it that your watch has some nickel in it. My Mom could only wear something that was 14k gold and nothing else. So, she just stopped wearing all jewelry. If she wore a cheap necklace she would get an awful itchy rash around where the necklace was. If she wore something without nickel it would go away.
A few years back when I started really knitting like crazy I would get awful eczema. I tried everything and nothing would clear it up. It wasn't until I got pregnant and I pretty much stopped knitting in my third trimester that all my eczema seemed to magically disappear that it finally dawned on me that my needles had nickel in them, the same thing that my Mom had problems with when she was my age.
I also notice carbonated soda flares it up too. I'm a diet Coke addict and when I was pregnant I stopped all soda. If I drink some at work now it will flare me up all over again and when I stop drinking it I seem to have everything clear up. I read on some internet board that a lot of adults with eczema were noticing the soda connection though I'm not sure if it's the caffeine or something else in there that really gets it going.
I'm glad you are possibly helped by this info. Trust me, I struggled for years and years with this. I even had to wear big mesh bandages around my hands in the winter from all the open sores I would get on my hands. It was so embarrasing because it looked like I was in the boxing ring! ha ha ha