Do you have a long pair of feeder tongs? It was something I used to do as a new owner was hold rats by hand. My snakes would target my hand sometimes, since it smelled like rat and was a warm moving target.
Something like this: tongs link
I agree, it's probably just too soon and he needs time to settle in. They can be very skittish as babies, but they can go longer without a meal than you think. I'd just give him a few more days to settle in completely before trying again. How are you feeding him, though? Make sure the mouse is completely thawed and heated up enough to be apatizing. I get my best feeding responses when I use a pair of tongues like these. They're not mandatory or anything, but I definitely have my snakes eating the most consistently when I use them. It may also be best to wait until you see him out and about to try to feed him, since he may be out looking for food and you'll know he's comfortable when he's out. Some baby snakes hide all the time when they're little until they've grown big enough to feel more secure, but you can help him along with the "feeling secure enough to explore" thing by making sure he has lots of substrate, plenty of hides, and tons of leaves and foliage he can duck under.
Something like this “aquarium hardscape tongs”, a flashlight, keen eye and some patience, will allow you to fish the oil cap out of your gas tank. Good luck