chinese mp4 watch backlight dim?

Anyone had a problem with the backlight? it's never been the brightest of things, visible best in the dark or dusk or at least shaded with your hand cupped round it, but recently my watch just went off, and when I switched it back on and ever since it really is only visible in the dark. I thought it may have jumped to the dimmest setting but as far am I'm aware, there is no way to adjust screen or backlight brightness. Any ideas?