Blood clots form when blood thickens and blocks blood vessels, which can lead to serious conditions like heart attacks or strokes. Symptoms are often mild, so knowing the warning signs is crucial. 1. Swollen CalvesClots often form in the calves (DVT), causing swelling, warmth, redness, or discoloration. 2. Leg Pain or TendernessPain in your calf, foot, or leg—especially when squeezed—can...