How long do you do it for each day? At what amperage? What do you add to the water? What has worked for me is every single day until my hand is completely dry for 1 hour, but I do notice and can see part of my hand that has become dry. What happens though is I start to get blisters in the parts that are becoming dry and it gets painful, but I can tolerate it.
I would also recommend exercising and changing your diet, because I think hyperhidrosis needs to be fought on multiple fronts. I think iontophoresis alone may be helpful, but attack it from other angles as well, with meditation, exercise, healthy eating, avoiding stress inducing situations, like a number of things that will help stop it.
What I have done is I have started to change my diet by cutting out caffiene and a lot of sugar, no alcohol, ride my bike when I can, I also was prescribed some anti anxiety medication clonazepam that helps me calm my nerves. I find when I take one I'm just more relaxed and thoughts aren't racing through my head.
Again, if you haven't done so already, try table salt in the water. I used baking soda before and it had no effect.
I'm not saying this is a solution but for too long I have let HH run my life, now its time for me to run HH. And it really requires a major life style change. I had to give up a lot of buddies because they drink a lot of alcohol.
A sort of "I will not rest until I have you under control" type thinking. And I want to help everyone here in any way that I can because I know how much of a nightmare HH can be.
This might help while doing the iontophoresis too, write down on a piece of paper "I am going to conquer HH." Over and over again. Even say it in your head over and over again "I am going to conquer HH." Keep repeating it as long as you want until it finally sinks in, then you sort of become honed on controlling it, it becomes your main focus.
Or even only drink when you are thirsty. Only eat when you are hungry. Don't wear socks when you are relaxing at home. I know its hard, and I'm just throwing some suggestions out there, but anything so simple could cure this annoying condition.