That sucks! At least you can still work with it after it's washed. I usually dry mine on regular dry and take it out as soon as the dryer beeps. I smooth it out by hand and fold. Pressing/ironing comes later when I need to use it.
Hang in there and hope the blisters heal soon.
BTW, I don't prep the pieces. I'd rather deal with the tangles. Not really a big problem for me.