Don't worry, I'm sure that's very rare.
I had chickenpox at 26 so I know how nasty it can be when you're older.
There's not an awful lot you can do, but take paracetamol every few hours & keep cool.
(I made the mistake of thinking that I needed to keep warm but as soon as I got my temperature down I felt better).
Hope it's not too bad for & get well soon
And don't scratch! You could try a calamine lotion on the spots, but it tends to rub off very quickly.
Go to the doctor who will prescribe an anti hystermien aswell, which will help, the calamine only gives momentary relief, you end up caked in it ! The actual illness only lasts about three days, so you will start feeling better fairly quickly you will just look manky for a bit. I would be surprised if you died.
You poor soul !!!! I had it as an adult and ,although its rough, you will be fine.
Paracetamol should ease your fever and , as grumpii says, cover your itchy spots in cool calamine lotion.