I completely understand this problem. I've had palmoplantar HH my whole life and it made playing piano and flute very difficult. My hands would literally leave puddles on the keys and made my flute/piccolo very difficult to hold. I just had to keep towels/handkerchiefs with me and try to discreetly dry my hands when able. It's a lot harder to hide HH when you have shiny fingers and instruments!
None of the available treatments worked for me, and I had ETS surgery in 1999 when it was much less common. This has solved my palmo HH, but my feet still leave puddles if I go without socks and I've developed compensatory sweating on the back of my legs, which leaves interesting prints on piano seats... :roll: So, I still have to bring something to sit on.
I hope the iontopherosis works for you!