Leopard gecko, yellow with brown spots

I lost my leopard gecko yesterday around 3pm. He’s a small, bright yellow gecko with brown spots and a chunky tail, about 4 inches long, and he has a distinctive white speck under his chin plus a notch on the tip of his left hind toe. He lives in a 6x8 inch glass terrarium with a heat lamp; the lid has a tiny dent from a fall. I was by the Lincoln Park Conservatory area on Stockton Drive when he slipped out, and I’ve been scouring the area since. He’s been with me since I adopted him as a rescue; I’m really hoping to get him back—he’s the goofy, calming presence in my week.