Hi Liz,
It seems you're having some trouble with updating your Apple Watch, and I want to help.
Try these steps to delete and redownload the update again on your iPhone if you haven't already:
"If the update won't start, open the Apple Watch app on your iPhone, tap General > Usage > Software Update, then delete the update file. After you delete the file, try to download and install watchOS again."
Update your Apple Watch - Apple Support
If the issue continues, you might try to update directly from your Apple Watch:
"If you've upgraded your Apple Watch to watchOS 6, you can install subsequent updates without your iPhone:
- Make sure that your watch is connected to Wi-Fi.
- On your watch, open the Settings app.
- Tap General > Software Update.
- Tap Install if a software update is available, then follow the onscreen instructions."
Let me know if that helps.
Thanks for using the Apple Support Communities.