I'm a bit confused when you say your snake overall looks "dull". My snake's eyes only look dull or rather foggy when it is about to shed, not so much the overall appearance. But perhaps I am missing something.
Nanners, my snake, sheds frequently, and I know when it becomes dormant for a period of time, and its eyes get fogged over that shedding is right around the corner. Within days I see her (?) shed skin and things are back to normal.
How long have you had your pet snake? Do you know its habbits yet? How often do you feed, etc?
It's been several days since your initial post, did it shed?