Same thing happened to me, at just a few years younger than 30. After a hike along the AT in the Shenandoah NP, I literally exploded in PI blisters. It was horrific. Wanted to die. And Dr. Bronner is indeed, truly, your best friend at these times.
Another plant they have back there, and I've seen it out here, is something they call Virginia Creeper (back east). It's a 5-leaved, serrated edged, plant that looks sorta like cannabis, only the leaves are fatter. Whatever you do, don't huff it!
I got into this shit so bad once while on a survey crew, that I had to take the week off and just laid around the house watching TV and staying ludicrously stoned to dull the pain and itching.