Huge dent in bed (Jack Knifed)

*UPDATE: SO FAR I PAINTED IT THE FACTORY COLOR. DECIDING TO CLEAR COAT MYSELF OR A SHOP DO IT????.*

So when I bought my truck not long ago I had to deal with the previous owners trailer back up problem. So my question is...How do I get the son of a gun knocked out. I was tempted to use a big effing hammer but honestly this is my first good body work of this nature. I'd like to put new flares on but this huge thing kind of inhibits that. Doesn't have to be perfectly flat and flush, but would like it to look like there isn't a big dent from afar. I don't want to bring it to a body shop cause this is how you learn to do things yourself. Awesome site by the way. i have been on here none stop. I'm addicted so far.