warped air dam

[Marc]

Back in January I replaced all of the cosmetic pieces under the front bumper on my wife's 83' 500sl. There is a plastic piece, I'll call it an air dam, that bolts to the valance and runs from one fender well to the other. When I purchased this piece from the local MB Dealer it came rolled up in a plastic bag. After I installed it on the car the areas in the front are all wavy from being rolled up. I tried to heat it a little with a hair dryer but this didn't help at all. I thought that maybe when the weather got warm it might straighten itself out but this hasn't happened either. There must be some proper way to install this piece. Any suggestions would be greatly appreciated.

TIA

Marc