Oh no! I'm so sorry. I think you've done all you can do. We had a dog attack a couple years ago. Two hens were badly injured but I seperated them, cleaned the wounds, and applied blu kote as well. Both hens seemed to make a full recovery, but we didn't know the extent of the damage until half a year later. One of the attacked hens started laying shell-less eggs. No shell. No membrane. Just dropping yolk in the nesting box every so often. Her reproductive organs had been damaged in the attack. This went on for several months and gradually became more frequent until she began dropping the egg yolks while roosting. Shortly after they turned bloody and mucousy so we had to put her down.
What I'm saying is, if Oreo recovers from this, there could be more damage done beneath the surface that will cause worse problems later so be prepared. I know it's hard when it affects your children, but I have learned with raising my children up around chickens, and having them see the good and bad, it teaches them real life lessons that shape them into compassionate, caring little people. I wish you the best!