Hi
Apple advises that you should not continue using a damaged Apple Watch. Apple Watch is not user-serviceable and Apple does not offer a screen repair or replacement service.
If the issue is not covered under warranty or any other Apple policy (be sure to ask, with specific reference to the battery), then your Apple Watch may be eligible for replacement via chargeable, out-of-warranty service - or via AppleCare+, if previously purchased.
Contact Apple Support (mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider to arrange for your Apple Watch to be inspected and to establish your available service options:
- US: Apple Watch Service Answer Center - Apple Support
- Elsewhere: Select your country for Apple Watch service and repair information
I'm afraid that no-one here can ell you what Apple will decide in your specific case. You are not talking to Apple here - this is a user-based technical support community.