Mosquito Bites... HELP!!

Hello,
I was hoping to find some help for my 10 year old daughter. She's been
going to camp and comes home everyday with dozens of mosquito bites.
She wears insect repellent and reapplies often. She takes Benedryl,
but they still itch. She has scratched a 'lot' of them open and
continues to scratch at the others. Some of the bites are up to 3
inches in diameter (red and slightly warm) She loves camp, but the
bites make her miserable. Any suggestions on how to relieve the
itching? Or better yet, help prevent the bites altogether?
I'd appreciate any help you can offer.
Thanks,
Marguerite