THE VEHICLE WAS PARKED IN A PARKING LOT. I OPENED THE TAILGATE TO STORE MY GOODS. I BEGAN TO CLOSE THE TAILGATE. THE TAILGATE WAS BEING CLOSED BY THE REAR SWITCH AND THE LEFT EDGE HIT MY HEAD. IT CONTINUED CLOSING FOR AN ADDITIONAL 1-2 SECONDS BEFORE REVERSING AND RE-OPENING. IT RESULTED IN A LACERATION AND BLEEDING THAT REQUIRED FIRST-AID.