Just a update, I tried the Pedialyte, didn't work, he ended up passing away not long after I called my reptile vet after finding him dead who deals with exotics and she said its possible he was already sick when he was in the pet store. I informed the pet store, they apologised but admitted they only keep them quarantined for 2 days (imo not long enough) and they throw food in and don't watch them eat.

They offered to give me another for free but refused and got a refund on him/her.