To reiterate:
It is not currently possible to complete the update to watchOS 3.1.1, as Apple has pulled back the update.
Apple issued the following statement:
"A very small number of Apple Watch customers experienced an issue while installing watchOS 3.1.1, so as a precaution we've pulled back the software update. Any customers impacted should contact AppleCare, but no action is required if the update installed successfully. We are working on a fix for an upcoming software update."
https://www.cnet.com/news/apple-rolls-back-watch-update-to-save-your-devices/
To delete any downloaded watchOS update file:
On your iPhone, in the Watch app, go to: My Watch (tab) > General > Usage > Software Update - delete the download.