After a period of too much usage of ketamine I got a really uncomfortable feeling in the bladder region, although the real 'K pains' were located in the intestines for me.
Later on taking a lot of GHB had led to me wetting the bed on 2 occasions but after that it never happened to me again, I stopped using so much ketamine anyway and I stopped using GHB altogether january 1st. Apparently I am now more or less a healthy person again, but I still have to pick up my condition, it is bad for my age (25).
I am not sure how reversable the damage that is done usually is but scarring of the lining of the bladder does not sound like it goes away in a day to me...
Be really careful, ketamine really scared me in terms of physical damage!