Sticky key

Have Apple or an Apple Authorized Service Provider examine the laptop to provide you with a repair estimate (it will be expensive). If the liquid is only causing a physical movement issue with just this one key, then perhaps an AASP would be willing to pop off the key cap to try to clean the liquid from the key cap, scissor mechanism, and sides of the key bay.

You will need to get your laptop keyboard replaced and possibly some components in your MacBook. It may cost $100 to 700. 100 is just for the keyboard and 700 for the whole bottom of the laptop. This price is not a guarantee