Dear PufferPunk, I've made some stupid mistakes myself and let me just say that reminding yourself of your mistake isn't going to do you any good. It just makes you feel horrible and it won't reverse what's happened. All you can do is keep going, at least you have survivors and that's a wonderful thing!
I had a faulty heater on my Fang's tank and turned it up one night because it was a bit cold in the tank, and forgot about it and next morning jolted myself out of bed when the thought hit me that I'd not turned the heater down! The poor puffers, it was like 90F or more in there! I immediately started doing a water change to get some of that hot water out, and replaced with cooler water. They seemed to come out of it okay though and now they are some very rotund little puffers!
Anyway, you've given some really good advice PP and I say, "thank you" for all your help and inspiration!