The only illness I know of that results with white spots is ich, of course the clorox could have attacked the slime-coat and is basically irritated skin. Use stuff like bloodworms to feed the fish, not the little freeze dried ones the frozen ones you thaw out work better. Not guarenteeing the betta will survive but feeding them bloodworms helps give them a little more of a fighting chance. And make sure the betta has a place to hide while she gets well.
You'll need to make sure you changed out some of her tank water and put in a conditioner for it that removes chlorine because that clorox probably boosted the chlorine lvl.
If it is ich, there's treatment for it at any local store (even wal*mart). The latter answer would be the tougher one because she could actually burst if her skin wears away too much.