Hi
If redness, swelling, itchiness or any other irritation or discomfort is experienced on your skin around or beneath your Apple Watch or band, then Apple recommends that you remove your Apple Watch and consult a doctor / physician before wearing it again.
Apple advises that 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":