Wow, that sucks. I've had bad reactions to poison sumac before, but never anything so severe as you are describing. My worst reaction was with the sap of Euphorbia tirucalli, the innocuous-looking pencil tree. I didn't know anything about it when I pruned these bushes off of my walkway.
I went to hospital with raised blisters the size of baseballs on my arms; they swelled up over the matter of about an hour and a half. It burned me so badly that I still have a couple of places on my arms that won't tan. The hospital immediately immersed my arms in chilled alcohol to counteract the enzymes in the sap. I count myself among the extremely lucky that none got in my eyes; the doctor said that had that happened, it would have permanently blinded me. He also said that if I ever got sap on me again, the reaction would be ten times worse.
Now I wear thick denim and elbow-length rubber gloves to handle any Euphorbs. And I don't prune the pencil trees.
And on a lighter note - Alocasia / other Aroid sap may be caustic, but it's the best cure out there for ant bites, and the only remedy to reduce the pain of being bitten by a
Bullet Ant. You think skeeters are bad?!? I have been bitten twice to date by these little buggers, and that's 24 hours minimum of excruciating pain, cold sweats, and the shakes. I am now extremely careful about where I put my hands in the forest.