My dwarf hamster wont come out of his bed?

I have a russian dwarf hamster and the first two days i had him he was fine with being handled but now he wont come out of his bed he will just sit there and when I hold him he tries to burrow in my hand ive had him for a week but he seems really comfortable with his new home i also know that he sleeps at night and is awake in the day but he still wont come out