Dwarf hamster, gray/white, tiny blue harness

I lost my dwarf hamster, Niko, yesterday around 3pm near the Decatur Square on Ponce de Leon Ave. He's tiny, about the size of a ping-pong ball, with gray fur and a white patch on his left ear, and he wears a blue nylon harness with a small silver bell. I last saw him by the coffee shop near the square and I'm worried he could have slipped into a planter or under a bench. This little guy means a lot to us - he was a gift from my daughter. If you find him, please text me asap; I'm really hoping to bring him home.