I have Uninstaller and reinstalled both Gear app and app on my phone, even hard reset my watch. The very first watch face I synced worked, the second worked, the third worked after that I cannot change the face. It doesn’t give an error. It goes through the motions and when the screen comes back after going black for a second it is the original face and didn’t change…
I had a similar issue and found it was due to me using half a dozen different smartwatches - you need to tell Facer which watch you are using, on your phone under seetttings you find the right tweak to make?