Some keys stopped working after I spilled water on my Apex keyboard

[make_me_bad27]

If I find a replacement membrane from an apex RAW and switch it will it work?

 

[Aeacus]

KB membrane is just rubber part of the key switch. Though, for your issue, you need to find replacement switch or entire PCB under the membrane since most likely the water short circuited those specific keys. Btw, it's easier, cheaper and faster to buy a new KB rather than going through the hassle of locating, buying and replacing your current KB fried parts.