I Had A Test Today For DVT. I Was Told

I had a test today for DVT. I was told by the technician that I did not have a blood clot. I could see the vein, my untrained eye could not see a clot either but the vein was definitely swollen in the area where I have been experiencing swelling, soreness and pain. No clot so why the swollen vein? What next? Thank you.