Julia,
I can imagine how you must feel. By the time you read this, I hope Pepper is home!
Please also check in with local vets -- people may bring him in to have him checked if they find him or put up flyers there saying they have found him. I would think that at the local churches or shops people may put up found signs too.
Dogs are really good about finding their way home, even if it's a new place you've moved to, so keep that in mind.
Our cat Waldo was gone for three days while my parents were watching him and he's a house cat and not familiar with the area, let alone being outside. He found his way back. Pepper will remember the smell & the surroundings of his home.
Please keep us posted....... also, I hope your child is doing okay after the fall. What a weekend you must have had!
Caroline & Brendan