Underbody Skid Plate?

Please tell me someone knows where to get, or who make even, some type of underbody skidplate for 1998 Expeds. I was off roading last night and the two metal straps/bars that go around the gas tank got mud between them and the tank. This resulting in bending the plastic tank inward. Any suggestions please? Also, what effect does this have on the car having the tank bowed in slightly???