I had the trial one to try and stop my frequency issues. Unfortunately it didn't work so it was removed after 4 weeks. Mine was done under general both times.
Nothing to be alarmed about, just remember to switch it off before you remove the thing for a shower, because if you don't and it gets turned up and you plug it back in, it gives a bit of a shock!
I have no idea how it works if your nerves have been cut, as I thought the point of it was to kind of switch your nerves off?
I will be having my nerves cut - 2 weeks today I go in for a clam cystoplasty which is major bladder surgery where they cut it in half, sew a piece of bowel in as a new lining and to make it a bit bigger, then sew it up. After recovering from that, I may have to self catherterise for life. Going to the toilet a lot may not be life threatening, but it can be life limiting, which is why I have finally chosen to go ahead with such a big op. Am petrified though!
Good luck with yours, honestly, it will be fine. Not painful at all, is hard to explain, but is like a weird buzzing in one of your buttocks!