The oil is the poisonous part. Everything you touch will get the oil on it: doorknob, lightswitch, etc. Wash as soon as possible, keep burts bees soap handy. The blisters will NOT spread the poison, that is a myth that came from people touching the doorknobs, etc.
Story time: when my grandpa was a kid, a friend told him if he ate a handful of it, he would be immune to it. He was on his deathbed for three days, doctors said there is nothing else to do. But he came out of it immune to it.
Feral cat waterboarder