I don't know how long it takes them to "come back" but they don't run very far before stopping to see what spooked them.
I've spooked deer out of my yard as I left to walk to the mail box (1/4 mile) and when I got back, they were back in the yard. But those were "east of the big river" deer that were habituated to living around humans.
Often, the tail up, fleeing for their lives routine stops as soon as they get a bit of brush between them and you.