Beer, you could probably reverse that process and have a plain guitar again. Possibly the paint could be removed with a solvent that would not also harm the underlying finish. Or you could sand it off and restore the finish. PM me if you want more specifics. Caveat: any time you change the surface of the top (the sound board) you change the sound of the guitar. That's probably why people nix painting. Also because it's tacky.
I would think that the pigment in paint might make a difference in the sound, guys.
Blessings,
Barbara