Black sports band - wrist irritation

Stop wearing the band and get a different model band. It appears you have an allergic reaction to something in the current band.

You might want to try a support call to Apple for a refund, but they may not be able to provide one.

Get Support – Apple

https://getsupport.apple.com/

Call Customer Support (800) MY–APPLE (800–692–7753)

or online https://getsupport.apple.com/

or call AppleCare Support at 1-800-APLCARE (800-275-2273)

Outside the USA—Contact Apple for support and service by phone

See a list of Apple phone numbers around the world.

https://support.apple.com/en-us/HT201232

Thank you for participating in the Apple Support Communities.

We want to make sure you reach the right team for help with your device. We recommend that you contact Apple Support directly. Depending on your region, you may be able to reach them here: Get Support

See your physician first.