I always try to save different versions of a song as I am working on it so that I can go back and redo or delete tracks or effects after its mixed down and I hear something I don't like.
Just use the File>Save As each time you close and include the time or date in the title for easy reference or maybe the type of mod you did.
Has solved some similar problems several times.

If its a Realdrum track you could just try to regenerate that track without the metronome (if it's playing all the way through the song), delete the other track and fix the mix that way.
If it's a midi drum track maybe you can edit out the metronome in the Piano Roll window?
Not sure as have never done it.

Carkins