Kitten lost somewhere in bedroom,please help?

I just got my kitten today from the spca, and he is 8 weeks old. When we got home i took him out of the cat carrier and held him for a while and then he ran back in the carrier, so i left the room to let him get accostumed. I later found him under a small dresser. So i set up an area ( walled in by 4 3 foot high boards) and left him to get accostumed. He was cowering in the carrier still so i took the top off it to get him some light. Now he is gone. I have no earthly idea how he could have gotten out of his little penned in area, but I am freaking out. Since I lost him before, most of the things in my room are up already and i think he might be in the very unreachable corner of my closet. I have a cat and a boston terrier. Will he be fine if I go to sleep ( knowing that the other animals might come in the room) and how can i get him out?? Please serious answers only. I am too stressed to deal with dumb ones.