I have snakes that will do that sometimes.
With some snakes I can just re heat it and re dangle the rodent in front of them and they'll strike again and eat it.
With others i just put the rodent over the hot spot and leave it for a couple hours or even overnight. more times than not the rodent will be gone.

It might have just lost most of the body heat while she was figuring out how to eat it. Try to warm it up with a hair dryer and re offer it to her.

It will depend on your snake...just give her time to eat it and after a couple hours you can try re offering it to her or freeze it for next time if she'll take it. ( you said she killed it so when feeding live you could freeze the body and try and offer it to her next time)
good luck!