When the laptop has been turned on do you get the Windows startup sound, indicating that it has booted into Windows?
If not, try getting into BIOS on startup by pressing the Novo button on startup and check if you can get into BIOS with images on the display.
If so, try shining a torch at an angle close to the screen and check if you can detect any images at all.
If there are images to be seen, then there is a backlight problem with the screen. It may be that the spill blew the backlight fuse on the motherboard. Usually the fuse is mounted close to the video cable connector on the motherboard, so you may be able to check it with an Ohmmeter to see if it is OK or not. If the fuse is OK and that there is voltage at the fuse when the laptop is turned on, then it may be a problem with the display itself. If there is no backlight voltage at the fuse then the problem is on the motherboard. Check for any damaged components due to the spill.
If there are no images to be seen, then try connecting an external monitor the the laptop and check if it has a display at all. If the external monitor shows a display then check the motherboard’s video cable connection to the laptop display as there may be corrosion caused by the water which is preventing a good connection. Here’s the hardware maintenance manual for the laptop which will help you to dis-assemble the laptop to check the connections etc. If the video cable connection is OK then it may be a problem with the display although it still could be on the motherboard. Further testing would be required to determine where it is.