comfort to help

Your best policy is to let him hide or to take him further away from the scary situation. Then, once he settles down, encourage him to approach as close as he is comfortable to what frightened him. Feed him a few treats and then leave.
Most dogs bounce back from depression within a few days to a few months with just a little extra TLC, said Ciribassi. “Keep them engaged, do more of the things they like to do, get them a little more exercise, and they should be fine,” he said. And reward them when they show signs of happiness, Beaver said