I assume a DVT has been ruled out as a cause of the swelling. Other potential causes of the inflammation include infections, inflammations like bursitis, tendinitis, synovitis etc. Assuming one of the inflammatory causes, it may take 1-4 weeks for the swelling to subside. Aside the compression stocking you may also try elevating the leg, ice-pack application and some OTC NSAIDS for relief.
Hope this helps.
Thank you for your comment. I do not have any DVT's. The swelling has been helped by the stocking. The lump on my knee has not changed. The swelling is still very big. Also, thank you for giving me a time frame to expect some sort of change in the size.
I would suspect this to be one of the inflammations. The swelling around the joint may tend to be less resilient. I would suggest following the recommendations mentioned in the previous posts. Hopefully this should get better in a few weeks. However if the swelling or discomfort remains beyond the time frame, you may consider an evaluation by your orthopedician.
Hope this is helpful.