this thread is USELESS without pics! We gotta know how bad the bend is before a call be made to rebend or replace....
I've had marginal luck with plastic fenders on other quads by propping them up with tall soup cans on top of the tires and leaving them out in the blazing summer sun. The sun heats the plastic letting them sort of bend back up. Unfortunately, once you remove the cans they start to sag again but the cans were free and plastics are not!