Some people just take a long time to clot, and you might have nicked a small vein if you have any that are prominent on your legs.
Did you take an Aspirin or Ibuprofen in the previous 24 hours? That could do it too. If this is the only bleeding problem you have, not to worry. If you are having nosebleeds, gum bleeding, or really heavy periods, time to have your blood count and clotting checked.
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