a healthy snake can live many months without food. A few days without eating is nothing to worry about.
You've mentioned the snake was eating ok before. Has the snake been pooping regularly too? A snake will generally poop about 2 to 4 days after eating. If your snake is constipated or holding its poop, it might not want to eat.
Reasons a snake might not eat - 1). About to shed (snake might refuse food before, during or after the shed), 2). Temperatures not right in cage (if a snake gets too cold it can't properly digest its food, it might also refuse to eat), 3). Something has changed recently to upset snake's routine and he might need time to re-adjust (have you moved the snake to a different cage, changed the layout of the cage, moved the cage to a new location, altered the temps in the cage?), 4). Snakes will sometimes go off their feeding during mating season. This is especially true with males. (However it's not mating season right now so this is probably not an issue), 5). illness or intestinal blockage (is the snake constipated, has it been pooping 2 to 4 days after eating?)