Swollen left foot for 6+ years, suddenly getting worse. now swollen up to knee. tight skin. red. not warm. blood test, xray & pulse all normal. ideas?

Evaluation ASAP: Even without pain this should be evaluated ASAP. It is always a good idea when something supposedly stable suddenly changes.

Foot swells now leg: I would worry about the circulation in the leg. Perhaps a vein is not working well to drain that leg or perhaps something is blocking the natural flow of lymphatic fluid. Certainly it does not sound like a kidney or heart problem since you only have one leg involved. I would also worry about it being red which implies infection or inflammation. You may need further testing

Need US of veins: Should see doc to have a Ultrasound of veins as a blood clog is the prime concern. If no clot, then severe lymph or venous insufficiency or infection.