Gray dwarf hamster with white chest patch

Yesterday around 3pm I was near the Billings Public Library on 4th Ave North when my gray dwarf hamster, Niko, slipped out of his tiny carrier. He's the size of a ping-pong ball, with two-tone gray fur, a white chest patch, and a pink nose; his left ear is slightly smaller and there's a faint white stripe along his back you can only see up close. I’ve had him since a gift from my sister, and he means the world to me. If anyone found him, I’d be beyond grateful to get him back home.