4. Tenderness

Usually a blood clot may be somewhere deep within the leg, but you will still know that you have it since you will feel how tender the skin surrounding the clot is to the touch. Make sure that you do not see the veins below the skin in the affected area. If they are visible, then you are very likely to have a blood clot at that site. You should also know that tenderness can occur in both legs, even when only one is affected by the blood clot. See the doctor if you have noticed tenderness or pain.