IMO, when any snake suddenly refuses food the first thing you should do is check for an upper respirtory infection (the common cold). Yes, snakes do catch colds. most people believe the sympton to look for is clear discharge around the nose and mouth but frankly, this is a long time to wait and at that point, your snake is actually VERY sick.
Pick the snake up and gently pinch his head (So that his mouth stays closed) and stick his snout in your ear. Seriously, stick his nose in your ear far enough so you can listen to him breathe. Pretend you are putting a pair of ear plugs in your ears-that's a good depth. You may hear a few "clicks". Matter of fact. that's exactly what it sounds like: "click.....Click.....Click....etc.
This clicking sound is a sign of an upper respirtory infection.
Your LFS should have Tetracycline Tablets (TC). Add one tablet per day for 5-6 days and your snake will be cured and should be a good eater too! Make sure you disolve the tablets and use 1/2 the usual amount of water.
I also recommend keeping the tank nice and warm and avoid handling him as you treat him.
I will be traveling the next few days and therefore won't be able to defend myself! Yes, I know it sounds strange to stick a snake's nose in your ear but trust me-this technigue is the only way to listen to your pet's breathing pattern. Clicking sounds=congestion. If you doubt what i'm saying at least treat his water with TC. This does no harm and will stop his cold from turning into a very bad situation.