Relax!
They are notorious for random fasting, especially males. Mine hasn't eaten in almost two months now.
Remember, they have a very slow metabolism so if your husbandry is in the green chances are he's just not hungry. It can be nervwracking, ask anybody here, buy just keep trying weekly on feeding day. Try not to offer every couple of days because that can stress him out. If he doesn't look like he's wasting away I would say you don't really have anything to worry about. I assume that since you're feeding pinky mice that he's a young one?