If your XIAOMI Mi Watch Lite is stuck or frozen, You can perform a soft reset operation. Check out how to force restart Android. As a result your XIAOMI Mi Watch Lite should reboot and start running again. Click here to find out more about soft reset operation.
Let's start by pressing the Side button to wake up the screen on your XIAOMI Mi Watch Lite.
Then press and hold the Side button. Keep holding it until the device turns off.
After the device turns off, release the Side button.
Then press the Side button to turn the device back on
Source : hardreset.info