Sure. But biometric authentication for WebAuthn or the related mechanisms built into iOS and Android themselves only takes place on your device. So at the extreme to "stop" you can just replace that device, I understand most people do that every few years anyway.
WebAuthn doesn't end up with a third party (say, Facebook) having biometric data, what they've got is just a public key and an identifier. Your device is signing to say it checked you are still you, whoever that is. It does not promise how it did that and there's no reason a web site would care.
Your biometric data (if that's how you authenticate) is only needed by your device, to verify this is still you when it makes that claim. So any changes (e.g. you decide to use your other hand) are a local device problem, no need to tell any third parties anything interesting happened.
WebAuthn doesn't end up with a third party (say, Facebook) having biometric data, what they've got is just a public key and an identifier. Your device is signing to say it checked you are still you, whoever that is. It does not promise how it did that and there's no reason a web site would care.
Your biometric data (if that's how you authenticate) is only needed by your device, to verify this is still you when it makes that claim. So any changes (e.g. you decide to use your other hand) are a local device problem, no need to tell any third parties anything interesting happened.