Post-operative swelling can cause congestion, making it difficult to breathe after surgery. This is something that resolves over time. Post-op swelling can also give the appearance of asymmetry and irregularities. 18 days is still soon after surgery, and you will need some time to heal. I would recommend following up with your surgeon regarding any post-operative concerns, as he/she knows the details of your procedure and will be able to advise you. I hope this helps, and I wish you the best of luck.