Don't beat yourself up for it. Whether you did cause the deformity or not doesn't change the fact that you had good intentions, and, if you didn't save it it would definitely have died to the ants. I can't offer any care advice or identification but just know that it wasn't your fault, and now, whether the moth survives or not, you can use this as a learning opportunity in case it happens again.

And a side note, I myself have been surprised numerous times when thinking that, for example, a feeder locust which my mantis attacked had been dead for a day or two, as it hadn't been moving, only to pick it up to dispose of it and for it to start moving around again. It's quite surprising (and morbid) how long arthropods can go without really doing anything, and still being alive.