Oh my gosh!! I'm so sorry for you. Fire is one of my biggest hair fears, and sometimes I catch myself being foolish while cooking and it scares the bejeezus out of me. Now's probably a good time to be grateful that it wasn't worse.
Is fire bad for your ends? A hairdresser told me that there's an old technique for trimming split-ends out of layers using a candle and burning the edges. I've wondered since then if a burned off hair end would be bad, and sometimes I've wondered if sealing off the ends with fire might actually help prevent splits. Hmm...
But yeah. That must have been really scary, I'm so sorry it happened to you.
How do you know you have damage?