Everything that's been said is great advice as far as figuring out why he's burrowing and why he won't eat. Ball pythons are such picky eaters especially when their conditions arnt right.

Im curious though on how you present the mouse after its been thawed. He will most likely ignore it if you just lay it next to him. If you haven't already I'd get a pair of tongs or something to dangle the mouse in from of him. A little zombie dance seems to get them more excited and interested in eating a FT rodent.

I'd also suggest trying feeder rats or mice from a different source? I've had terrible luck with the artic mice. I noticed when they thaw out they are normally covered in urine and look like someone smooshed them. My snake won't touch them. But he will devour FT mice/rats from anywhere else.

Not that this will solve your problems without addressing your other issues first. Just a possible helpful tip.