If your Apple Watch is disabled because you forgot your passcode or entered an incorrect passcode too many times, you can reset it from either your Apple Watch or iPhone and set it up again.
Important: If Erase Data is turned on, the data on your Apple Watch is erased after 10 failed passcode attempts.
Put your Apple Watch on its charger, then press and hold the side button until the sliders appear.
Press and hold the Digital Crown to show the Erase all content and settings screen.
Tap Reset, then tap Reset again to confirm.
When the process finishes, About Activation Lock on your Apple Watch.