As I just said to someone on iHerp, welcome to the world of Ball Pythons!

They can and will go off feed sometimes, usually for no reason at all - and as adults, can easily fast for multiple months (one of mine went 10-11 months) without any ill side-effects. But if you notice OTHER symptoms, like wheezing, mucus, lethargy (hard to tell with BPs, lol), etc, or if they lose a LOT of weight, that is when you really need to worry.

Any chance the baby is going into shed? That's the most common reason for a sudden disinterest in food, as most BPs prefer to abstain during the pre-shed and shedding period. If you're not sure, look to see if the belly is pink... they should also look a bit "dull" in color, like not as bright as you're used to seeing him/her. Other than that, your guess is as good as mine! Just keep trying, warm up the mouse a bit more, or try live if this continues much longer. Good luck!