It's gone forever. You'll need to redeploy the application that was overwritten, if it is production.
My suggestion to you is create a deployment process; so this never happens again.
I typically publish to file system (aka my computer) Each VS Project has its own profile (.publish) that saves that information for me. Then I use RoboCopy to copy to the destination, either test or prod. And most importantly, I use RoboCopy to create a backup. This way, if the deployment is screwed up, then I have a backup I can put back out there in seconds. There are new ways to do this, but RoboCopy has served me well.
YouTube has
tutorials and examples.