There is a big article on wiki if you are able to perform electronic repair or at least able to use a multimeter.
https://logi.wiki/index.php/Backlight_Troubleshooting[br]
since there was water damage on the backlight connector first thing you have to check if it really outputs an image, just use flashlight and look for apple logo or some interface items. [br]
if there is no image, most likely you will see that edp_aux line is shorted to ground. unfortunately it is not fixable on all 13" devices because this line goes straight to the CPU.[br]
post hires photo of visible damage on edp connector and in most cases it would be clear.