How Do I Fix An Apple Watch Digital Crown?
If your Digital Crown is unresponsive, turn off your Apple Watch and make sure it's not connected to its charger. Remove the band from your Apple Watch and then hold the Digital Crown under lightly running warm water for around 10-15 seconds. Do not use soap or any other cleaning product, just water from your faucet. While rinsing the Digital Crown, turn and press it repeatedly. Then dry your Apple Watch with a non-abrasive, lint-free cleaning cloth. Hopefully rinsing the Apple Watch will free any debris trapped between the Digital Crown and the casing.
If after all of that your Digital Crown still doesn't work, please make an appointment at your nearest Apple Store Genius Bar.