It would be ideal to fit it into your daily macros, but if you've been dieting for a long time it might be a good time to incorporate a refeed or cheat meal. I find that I usually get cravings after dieting for a few weeks, and its a good sign that my body needs some extra carbs. Everyone is different when it comes to this though, and make sure your small sweets craving doesn't turn into a binge on crappy food.