I can understand your concern and I hope you know I respect your story and opinion, but the fact that the machine you used was NOT a Zapper and WAS higher voltage says a lot! There is a very big difference in electricuting yourself and applying electical current at low voltage to your body. I have never heard of anyone at all who has had unsafe experiances with a 9 Volt Zapper. I know of some general Zappers at 12 Volts, and I would be a little bit scared to use those!! I am very sorry to hear about your accident.
It would be great to know all of the details so that people will know not to do what happend to you. What was the voltage, what was the machine? How long did you do it? Was it AC or DC?