display black but touch screen works.Help?

Hi,

As a DIY repair all you can initially do is to temporarily replace the screen and then check if it works OK or not.

Here’s a video that shows what to do.

Replacement screens are available online. Just search for Xiaomi Mi 9 Lite display to get results for suppliers.

FYI using rice to fix problems in electronic devices, caused by water damage is a myth. It doesn’t fix the problems caused by the corrosion that occurs when water comes into contact with electronics and worse if there is still power connected as well. There is always power connected to certain parts of the systemboard in a phone, even when it is turned off. This link may be of interest. Rice is for dinner, not repair.