Painful rash

I have no idea what has caused this and it's been so horrible for Eb. At first I put it down to an Orange she had 1/3 of a segment of (flesh only). She has been offered orange before but has immediately given it back. The recipe I was doing called for the flesh only with no 'membrane' and she decided to put it in her mouth, but rejected it after a short while anyway.
The next morning (Thursday) - this was what I woke to.









I took her to the Doctor that morning, but when we went outside it seemed to settle a bit and wasn't as bad at the surgery. They suggested 'Claratyne' which I proceeded to buy - but when I gave it to her she seemed to flare up. I called the Chemist and they suggested Phenergan. That helped the itch, but didn't settle the rash. Poor child was undressing and writhing on carpet on the floor to scratch herself.
What was interesting about this rash is how it changed and moved around her body. There was absolutely nothing on her face until Friday even though it was so bad on Thursday.
Friday she was worse though. I was due to leave for South Australia first thing, but decided to go back to the Doctor. They were a bit concerned and took some tests but said she wasn't contagious and keep up the Phenergan. Thankfully, by Saturday afternoon it was all but gone. The doctors don't think it was an allergic reaction because it went on for too long. I guess I'll find out one day when I try orange again...if I'm ever game! I don't ever want to see her suffer like that again.