Babies can be good at escaping. I have a couple stories.
The first, I was when I was renting an old farmhouse, that was two stories tall. I had the snakes in an upstairs bedroom. I had this tiny hatchling, that on feeding day, wasn't going to wait for feeding, and she squeezed through a tiny gap in the hatchling rack. I tore the room apart but couldn't find her. I set up a bottle trap in the snake room and went downstairs to the main floor. Later that night, I was watching a movie, and saw movement on the floor. There she was!
A few weeks later, she did the same thing, and escaped on feeding day! UGH!
I searched for her, and could not find her. It was winter, and after a couple weeks, I started to think that I wasn't going to find her.
We had a big snowfall, and I was about to go out the door to the back deck. It was right next to the wood stove, in the living room. I picked up the rolled towel that was at the base of the door to stop drafts, and guess who was curled up under the towel? She was cold and hungry, but she was fine.
I moved her to a different spot on the rack, with a tighter fit, and she didn't escape again after that.
The other story was here in my house that I now own. It was the first winter I was here. November, if I recall. I didn't close a bin all of the way, and a hatchling got out. I searched everywhere, and could not find her. A few months went by, and I thought she was long gone.
Springtime rolls around, and I went out the back door to let the dogs out into the back yard, and I look down next to the porch, outside, and there she was, curled up next to the porch. She must have brumated herself over winter.
I got her warmed up, and back on a feeding schedule (I took it slow since she hadn't eaten in a few months), she is doing well now!
Search at night, that is when they are most active.
One more story.
A friend of mine, local breeder, had a Cornsnake get out, and after 8 months, thought the snake was long gone. Turns out, a neighbor found him in his wood pile, outside!
Alive and well.
Don't give up!