I've wanted to post a follow-up to this topic for some time now, just in case someone finds it in the future via search engine.
Although I initially suspected that low-grade leather was causing the blisters on my hands, I found that switching back to the expensive stuff didn't help. I was truly puzzled, since I could handle finished leather products all day, but making them was out of the question. I stopped doing leatherwork for about a year due to this issue.
When I decided to give it another go in January of this year, I made absolutely sure I wore gloves every time I used any sort of liquid. Since that time, I've experienced no problems. If you ask me today, my guess is that I was having an allergic reaction to either the Satin Shene or the neatsfoot oil; both of which I used to apply with bare hands.
Lesson learned -- always wear gloves when applying dye, oil or finishes.
-Alex