If you experience redness, swelling, itchiness or any other irritation or discomfort on your skin around or beneath your watch or band, Apple recommends that you remove your Apple Watch and consult a doctor / physician before wearing it again.
Skin reactions can be a result of various causes including:
- Allergies (eg to nickel).
- Extended exposure to irritants (eg soap or sweat).
- Environmental factors.
- Wearing the band too tightly or too loosely.
More information, including tips from Apple:
- Cleaning and wearing Apple Watch - Apple Support
Includes "Tips to avoid skin irritation, or if you have allergies or skin sensitivities".
- Wearing your Apple Watch - Apple Support
- See under "Skin Sensitivities":
Note that there is no model of Apple Watch that has no metal or nickel touching the skin; the magnets in all models of Apple Watch contain some nickel.
If you are considering buying a different band, note that Apple recommends using only Apple-branded or Apple authorised bands with Apple Watch: