juvenile ball python WILL NOT EAT!!

[AbsoluteApril]

I don't know why he regurgitated the larger mouse, but when we fed him the first pinkie he ate that too, and kept it down.

It's possible the original regurge was because of the cedar, I know he kept the second one down and then you changed out the bedding (good!) but it may have caused that first one. Usual other causes of regurg would be temps too low or high, stress or disease.
The hatchling care sheet Deb posted is a really good one. I hope he starts feeding for you again.