Your theory is quite correct. That's exactly what happened. It can happen after a bone fracture as well and those blood blisters are actually called fracture blisters. They sometimes contain lymph, rather than pure blood.My theory is that the entire leg was so swollen and jammed up against the skin, the excess blood had to go somewhere, so it broke through the surface and formed blisters on the outside.
You've got it right once again.I am amazed at the huge urine output every night. I think on this particular day, I generated 2.5 liters of pee. For me, that is simply unheard of. My theory is that it is part of the elevation drainage system. The leg is "full to overflowing" with fluid (as we have already seen) and the urine output is the body's mechanism for eliminating it. I'd love to hear comments on that theory, please.