Swelling should not be a response to being dehydrated, that is def. an allergic reaction. Did you start with PG only juice or carts and get this reaction, then tried VG and got the same reaction? It's really hard to know what you are reacting to, but if it keeps happening, then it seems your choices may be limited. Did you talk with the doc at the ER? what did they tell you?
I found the PG made me dry out, spacey, almost having anxiety and muscle cramping, so I went to VG and did not have any problems, but I am 0 nic. vaper, so I could not blame the nic. only the other ingredients. Where did you get your VG from, e cig supply or the store? If you are reacting to the PG and they used PG in the VG mix (nicotine or flavor) you could still be reacting. It's just so hard to say, and I am not a doctor, nor do I play one on TV... good luck to you. I hope you can figure this out.