I'd try a smaller item, and then if that doesn't work, try a live fuzzy. If still no go, leave the snake overnight in a small container with a live rat pink.
Also I have better luck with troubled eaters by feeding them at night.

Your snake may just be getting ready to shed. I wouldn't get too worried just yet. Last resort would be to drop its temps to brumation range for a couple weeks or so, but I wouldn't just to that yet.

Good luck!