For whatever reason you need to uninstall the Watchmaker app and then reinstall it, you might want to backup your faces.
There are two main ways to do this.
Export each face - then backup the .watch files. After you reinstall the app you can simply import these files to use the faces again. This step requires you do each face one at a time for both export and import.
Plug in and backup - Plug your phone into a computer navigate to your phone and find the “BeautifulWatches” folder. Backup that folder or make copy of it on your phone, then uninstall the app. Reinstall the app and copy your backup of “BeautifulWatches” to your phone again. This will require no import or export.
Note: If you are having issues with app you might want to opt for #1 so you are not copy old app data only faces in .watch format. it requires more work but worth it if you are trying to troubleshoot app issues on your device.