Scene Recovery from a Standalone Build?

After mistakenly importing a new heightmap into my customized sloped terrain asset, I have lost all of my careful sculpting! I know - never modify the source asset. But, I built a test world as a standalone build for Windows where the original terrain is intact. Is there anyway to reimport the scene from the .exe into my original project? Or is my original data for the terrain asset accessible? Reimportable?