welcome 2 the site!

well u should let the snake rest and get used to its new environment before handling and feedin, and to tell if it has gotten used to its new environment u can try feeding it. If its goin in to shed then that might also be a reason for not feeding and i wouldnt recommend touching it while its in shed also.One more reason that it could not be eating is because of the husbandry(temps, humidity, no hide,etc).

Sand is a big no no for bp since it can cause impactation if digested and it can get in ur bps heat pits.

well good luck on everything and hopefully someone with more experience will also reply to this!