Well, I'd thought I'd update this. It's been two days and I haven't seen any more black spots. My RTB is still in QT, but so far we're looking good. I'm still confused as to how he got them, since I don't go to the pet store, I use newspaper, and no one handles my collection. Maybe they came from the wild herps around the house? Who knows. But I've treated the house the same way I treat for fleas and have PAMed everyone's enclosures, whether they needed it or not. Thanks everyone for all the ideas and help. Now let's just hope this is the last time I have to do this!