Please help me! My corn snake isn't eating!!?

Ok, I have a corn snake that is about 12inches long, and he shed like a month ago, and he's not eating!!! We've been buying pinkies (baby mice) and he's eaten them before, and the last time he ate was probably 3-4 weeks ago. But now, he won't even look at them! I've tried feeding him in and out of his cage. (putting him in a different cage to feed him) He has "privacy" so he's not like uneasy to eat because there is people watching him. What could be wrong?! I don't want him to die! pleeease help!!!!