The butter scotch taste is diacytyl. Sorry I don't quite understand, is it still in the FV? If it is just leave it there, perhaps rouse the yeast. The yeast should clean itself up. If you bottled your beer, give them a shake to resuspend the yeast and stick them somewhere warm if you can, again the yeast should reabsorb the diacytl
Have you tried this? Does it work? I've got a pale kit brew that has got a really strong diacytyl taste that really doesn't suit the style (I'm going ag now anyway but brew years resolution, stop using crappy yeast).
Going to try it with a couple of bottles regardless, won't make 'em worse.