Sounds like you've shorted out the keyboard, which in normal on a keyboard spill, Hook up an external keyboard and see if it works well with the machine before doing the repair. I have not done this repair on the 2015 model but have on the 2014. The keyboard from earlier models could be replaced with a lot of effort and removing about 86 screws. The 2014 was the best protected (in that I mean the cover on the underside of the keyboard is very good). This really helps to preserve the logic board. The problem with the 2014, and possibly the 2015, is Apple started using a type of peg instead of screws to attach the keyboard to the frame. There are a few screws around the perimeter of the keyboard. It looks to me like these screws are used to position the keyboard on the frame and then a machine presses these pegs in all at one time. Makes for much faster assembly but really complicates replacing it. On the 2014 I had to remove the screws then use strength and pliers to rip the keyboard out. Then had to go back and dig and drill some of the remnants of the pegs out. I then bought a keyboards and a set of self threading screws. I then replace the original perimeter screws to position it and hand drove the new screws in creating my own threads in the aluminum.
A. Here's the easy fix: replace the upper case, here's the $525 part: MacBook Pro 13" Retina (Early 2015) Upper Case Assembly
Still requires a complete tear down of the machine, This is assuming the trackpad is not involved.
B. Attempt to do what I did yourself.
C. Send it to a really good Mac professional. It's still going to take him four hours to do it correctly. But will probably only cost $350 to $400 to do it. According to what you spilled and how much clean up time the frame may need.