Keyboard water damage, can I replace just the keyboard?

I'm looking to get some advice. My partner has a Mid 2012 Macbook Pro 13". She spilt some water on her keyboard.

The Macbook boots up fine, the backlight works fine. However some of the keyboard keys malfunction (mostly the bottom row). For example, when you press 'c' key it types 'cd' etc...

Does this mean that it is only the keyboard that is damaged? Can I buy a replacement keyboard and replace it myself? Or does the malfunctioning suggest it's another problem?

Any advice would be appreciated, thank you!