In skinstudio the default is promt to save every time you apply the blind.... you can turn this off in tools ---> preferences..... else dont click save if you dont want the changes to be permanent....... one thing you can do is all the orgiginal skinparts is still imported into the skin and should show up in the list.. unless you have saved over it with the new pic with same name then its gone.....

I'm pretty new to this, but true, making a substyle would've been the thing to do is retrospect.  That way I'd have all the original files if I needed them.  However there still should be a a Go Back/Undo option.  Thanks for the comments so far.