Hi Ann,
Sorry I missed out giving fdk on all the parts of this story, but I did find it very haunting.
You asked how you could make Clark's conversation with Perry seem to be an intervention by the Sandman.
Perhaps you could just emphasis what you already started by showing Perry's appearance change. Maybe a shadowy figure imposing itself on Perry's body. You could perhaps have Clark feel as if he's in some sort of trance as he listens to Perry speaking... then as the conversation ends both men return to total consciousness. You also could do all this from Clark's POV, letting us see the transformation through Clark's eyes.
The whole of your story has this sort of dream quality, so I don't think this would be too far out. However, this is only my suggestion and I'm sure you've already found your own way round your problem... or someone else has given you advice. Actually, I don't really think it's too much of a problem in the first place.
I did like your wrap-up and you can be as waffy as you like in my humble opinion.
Yours Jenni
