it's powdery mildew, remove the buds in bag that are covered with it. powery mildew will only spread if there is moisture in the bag. Dont close the bag let it breed some fresh air. Move the buds around in the bag. Powdery mildew is a plant killer when it happens in flowering stage. You are lucky it's only on a couple of buds. Dont smoke the contaminated buds, it's bad for your lungs. And when it's dried correctly you can always put it in a freezer bag and stick it in the freezer it will remove some of the rotten smell from the good buds.