This is called clotting. Clotting slows down bleeding. Press on the cut to help slow down the bleeding. You may have to apply pressure for 10 minutes or more for a bad cut. Sometimes a cut needs stitches.
Stitches help the cut heal.
Apply pressure to wound to slow or stop the bleeding. See your doctor right away for advice on getting a tetanus shot. Monitor for signs of shock. Put on disposable latex rubber gloves, if available. Apply direct pressure to the wound using a clean cloth or sterile bandage.