Help my 3 year old cut off her hair? And its BAD!?

i had just got her hair cut he day before. It was a shoulder length bob and it was so cute. Well i put her down for a nap and evidently my 7 year old left some scisors out and she completly cut off one side of her hair. It is almost to the scalp in one spot. The one side actually looks like a mullet. I am so mortified! How do i fix it? And has your child ever done this? How did you deal with it?