A section of my keyboard has stopped working

Model and OS: Macbook Pro (13 inch, Late 2011), mac OS sierra, v. 10.12.3

Hey everyone,

A couple of weeks ago I spilt a very small amount of water (a teaspoon or less) on my tracker pad - I quickly wiped it down but the cursor was freaking out so I shut down/disconnected from power and left off for 48 hours. It has since been fine, although there's periods where it clicks, zooms, jumps about. Whilst this can usually be overcome by clicking hard or restarting, this led me to plug in an old Microsoft mouse for convenience (about three weeks after the initial spill), and within a hour of doing so, a section of my keyboard suddenly stopped working.

Strangely - when logging in to my user (which includes characters from the missing keys), they appear as a hidden characters when typed, although the password is incorrect.

Any ideas what the exact issue is here? Never had any hardware issues with this machine before. Any help or suggestions are greatly appreciated. Thanks in advance