Touch Bar stopped working after water damage
This sounds like you'll need an SMC/NVRAM reset. 


Shut Down your Mac and unplug everything.
On your built-in keyboard, press and hold all of the following keys. Your Mac might turn on.


Control  on the left side of your keyboard
Option (Alt)  on the left side of your keyboard
Shift  on the right side of your keyboard

Keep holding all three keys for 7 seconds, then press and hold the power button as well. If your Mac is on, it will turn off as you hold the keys.
Keep holding all four keys for another 7 seconds, then release them.
Wait a few seconds, then press the power button to turn on your Mac.


If this still doesn't work, shut down your Mac, then turn it on and immediately press and hold these four keys together: Option, Command, P, and R. 

You can release the keys after the Apple logo appears and disappears for the second time. 

If ALL of that doesn't work, probably go to an Apple store (assuming they're still open where you live).

Sources:


Reset the NVRAM or PRAM of your Mac - Apple Support
How to reset the SMC of your Mac - Apple Support