I would suggest not handling him till he is back to eating, as hard as that is when you have a new pet. Some times it just takes a little while to get settled in fully. Also, rather than trying every couple days to offer him food, give him a week or two in between attempts, they can go a good long while without food as long as their body is in good condition (which his is) and sometimes offering too much makes them wait even longer. He looks like he has a tiny bit of stuck shed on his neck, might bump your humidity to 60-70% for a few days to help that along.
The rat is pretty darn cute too :P