I doubt that the humidity was the problem. When you re-potted was the soil dense and heavy? It is possible that the soil may have appeared dry on top and actually been soggy deeper in the pot.
It may still recover especially if you have it in a decent, free draining soil now. Treat it like a big cutting. Keep it warm, you might even try placing it under glass, or inside a plastic bag, to help keep humidity up without having to water the soil. If you take this route the soil will not require much in the way of additional watering for a while. Water it well once then just keep a close eye on it.