I had one escape while cleaning cages once. It was a flighty one, so I had it in a toilet paper cardboard tube while giving the cage a thorough cleaning. It was fine in there until I put it back in the cage, when it promptly spazzed and ran up the side of the cage and jumped. I certainly wasn't expecting that. It made for the corner of the kitchen where there's a hole in the wall... well... I wasn't expecting to find him again.
I did a thorough search of the kitchen, using a mirror and flashlight to check under the lip of the cabinets. I left out food and water near the corner and checked every time I went into the kitchen and still no go. Finally, about five days after the event, I went into the kitchen one night to get a glass of water and there he was, sitting on the edge of a cookie sheet I had sitting next to the sink ready to be washed. He was definitely not in his best colors, but a few days later he was looking in top condition once again.
Now I never take my geckos into the kitchen with me while cleaning. If one ever does escape again, it's far easier to catch them if they're in their usual room. There's less inconvenient places to search and as far as I know, no holes into the walls. I would just say to be patient and be calm, and arm yourself with a flashlight and make another search at night when your crestie is likely to be more active.
Good luck!