For an entire year after your surgery, your nose is continuing to heal and take on its final appearance. During that period of healing, it’s not unusual to see your nose fluctuate in size and the amount of swelling. You manipulated your nose quite vigorously, so that is the most likely explanation for the sudden increase in swelling. It’s unlikely that at 4 months out cartilage would have been displaced, but also a possibility. Give the swelling some time to settle down before you start worrying about cartilage shifting, and try to be more gentle blowing and picking your nose.