Aww bless it.
I'd suggest leaving some strong smelling tempting hamster friendly food out in a pile (or piles) near where it came out from and some water as it's probably dehydrated (not a tippable thing though unless you want a wet floor).
Put a little box (like an empty washing tablets box) on it's side with some fluff in, newpaper strips or preferably softer, inside to make a tempting cosy little nest.
Hopefully it will attract hammy and you can get him that way. He is likely to leg it if he hears you come too near so worth taking a light box you can put over the bed, be quick though as they're like houdini!
There are places which will take rescued hamsters, just ring your local animal rescue and they should be able to point you in the right direction.