unfortunately, you will have to get the tailgate open to repair it. Use a big flathead screwdriver and work the latches lose one side at a time.
You will then have to disconnect the rods from the handle, you will see a yellow plastic clip on the handle inside the tailgate, pop the clip off the rod and you will be able to disconnect the rod. Everthing unbolts and comes out of the tailgate from there.
From there, you can either get a new handle, or do what I did, I'll try to explain it, I have no pics so hopefully its understandable for you.
I took the rods out of the tailgate. The end that attaches to the latches is a big U. What I did was add some weld beads to the inside of the U shape, basically making the rods shorter. This made my tailgate open like brand new.