i was wondering if you ever found out what it was?
If your bumps are near the transition 'zone' of palm and arm skin then I have had those for years and they don't change. If the bumps are well with in the palm area then I would suspect warts, but watch for growth or change they will indicate the need for treatment. I have had warts on my palm too, and they grow very slowly and in 10 years are still only a very minor blimish that I have to look closely to see. Good Luck. Illusioneer
I'm not sure, but they certainly don't sound like warts or poison ivy or anything contagious. My best guess is that they are pores made more noticeable by waterlogging your hands. I can't imagine they have any significance, but if they worry you, let a doctor have a look when they're visible.
Take care.
Dr. Rockoff