[Razor]

Hi and welcome to HC!
Dwarf hamsters are usually very active and love burrowing. How much bedding does your cage have? Preferably it should be around 10-15 cm. Consider using a box with no base and one side cut out for the door as it's nest. Place it on the substrate and he'll eventually get the cue. Also, what is you cage size? Does he have enough toys to keep his mind occupied? Is his wheel spinning freely? Do you give him out of cage time everyday? And finally, is the room in which you have kept him cool? Temperatures above 23°C can start becoming very warm for them. If this is the case, there are several ways to cool him down. One of the easiest is to place a clay pot on its side for him to rest. Alternatively a granite slab work well. But nothing like lowering the room temperature.