No matter what it is, first adjust the brightness of the watch case, small sun and black and white buttons under your monitor or at the lower right.
If it is not normal to adjust to the highest level, there are two situations: if it is LCD, then the monitor is broken and sent for repair; If it is flat, let it stay for a while. If you use the screen longer and longer, it will become brighter and brighter after ten minutes, which is why it is affected by moisture. The indoor humidity is relatively high, just leave it on. If it stays on like this, it's broken. Go to the maintenance procedure.
I hope I can help you.