What if doing a hard re-set still doesn’t bring it back?
How to fix your Apple Watch when the hard readies not bring it back from being frozen?
Apple Watch
How to fix your Apple Watch when the hard readies not bring it back from being frozen?
Apple Watch
In that case you'll have to send it in for service.
Check this article about your options:
What if doing a hard re-set still doesn’t bring it back?