You can save it, the butterfly should be just fine if the chrysalis wasn't damaged. There are a couple of ways to keep it, so the butterfly will have something to climp up when it ecloses. If you have mesh hamper, or one of those bughouses with mesh walls/roof (at least 4-5" high), just lay the chrysalis on the bottom on a folded paper towel. You don't need to try to hang the chrysalis back up- the butterfly knows to try to climb up so that it can expand its wings.
Another way, if you have some extra window screen handy, is to cut a piece of screen that you can roll up and put inside of a plastic container- there's an image on the forum here somewhere, I'll add a link when I find it.
Be sure to keep any cats (felines) away- mine have been known to chase those fluttering wings!
Good luck, I'm sure some more people have good suggestions.
cheers - Scott
Waystations 15 & 629