A blood clot in your leg that is associated with deep vein thrombosis (DVT) can cause your lower leg to be sore, swollen, and red. A blood clot that develops deep in the veins of one of your legs can result in serious complications. If the leg clot doesn’t dissolve naturally, it can travel through your veins, and cause a pulmonary embolism eventually. However, there is no report about it travelling up to your hip.
Blood clots form in the legs due to poor circulation, injury to the veins, a side effect of medication, or complication after surgery. Sitting for long periods of time when flying or driving can also increase your risk of deep vein thrombosis. Because of the potentially fatal complications of a blood clot deep in a vein, you should never ignore signs of DVT.