Your skin may become irritated while wearing Apple Watch, as well as any other watch or accessories. This can be the result of allergic reaction or incorrect approach to wearing of the accessory.
Your watch may become wet while you’re washing your hands, or sun-protecting lotion may get under the watch. It is necessary to wipe the watch and keep it clean. This helps to minimize the probability of irritation.
Apple Watch is equipped with gauges which work only at direct contact with skin. It means watch should not be worn with very loose wristlet. But do not overtighten the wristlet; otherwise the skin will not breathe.
Some versions of the watch and wristlets contain nickel and methacrylates. This is quite natural for a product of such type, and should not cause any problems, but if you are sensitive to these materials, you’d better reject magnetic wristlets.
If your skin becomes red, in case of edema, itch and other symptoms of irritation or allergic reaction, Apple recommends to contact your doctor before wearing the watch again.