Hatchlings can be picky. Ive got a ball hatchling at work who wont eat unless you rub the F/T mouse in live mouse bedding. Another who strikes, coils and then lets go because she cant figure out how to rework the mouse into a position she likes, and my own ball python baffles me with when she will eat or not.

I would try using a blow drier to spread the scent of the mouse around. Maybe get her/him worked up a bit? If it persists too much longer people generally reccomend a live rat pup, as they cant really injure the snake. Though I also hear once theyre on live its a tough habit to kick.