That looks like a Ford tailgate from here. And like Pete said you're in trouble.. :lol: Lucky the top cap covers a lot and like Charlie says take the access panel off Get a bar in there and beat it straight. Just fixed one last month that looked the same and wasn't that hard to beat it straight.
Also you can tack weld a piece of tin on the lip and use a moe clamp and a slide hammer to pull it straight.
The look in your hounds face is perfect. :rofl: