Neck lift

Hi I'm going on 7 weeks since neck lift procedure and I'm getting very concerned about the swelling under my left jawline. My PS wants to do an ultrasound to rule out anything serious that might be going on. I guess my question is can an ultrasound rule out inflammation, lymphatic vessel damage, seroma, hematoma, or excessive scar tissue? My biggest worry is somehow either the scar tissue or some other damage was done to my lymphatic system which might cause permanent lymphedema. So any doctor's professional advice on what an ultrasound can and cannot rule out would be of great help to me. Thank you