The reason of swelling as you mentioned is because of tight socks. The elastic of socks are tight enough to hamper the blood flow of the veins but they cannot block the arterial blood flow. Thus in the leg, blood comes through the arteries, but collect there due to impediment of the flow of veins (can't flow back to heart). This causes the swelling. The stagnation of the blood predisposes for the clot formation. There is nothing to be scared. Not all clots travels to the lung. Early treatment avoid all complications. It is (15-20 minutes) too early to make an impression. The 8 hours stagnated blood takes time to go back in the circulation.
With a known tourniquet effect, one can wait for an hour or two. Lie down with pillows on your whole length of the legs. Sitting with legs elevated does not help because at the hip the veins are compressed and they do not let good flow back.
If you see that swelling on the legs has significantly reduced (say 25%) and their is no appearance of the warmth, pain or tenderness, this means that venous circulation is very good. If the swelling does not go down at all, a visit to an urgent care clinic or ER would be considered.
Please remember, the visit is to rule out any chance of deep vein thrombosis (a physical examination and may be an colored Doppler study would give clarity).
With your presentation it would be less than 1-5% incidence of clots, but we don't want to take any chances. Please don't do massage.
Read about deep vein thrombosis (clots);
Please feel free for your follow up questions.