I had a mechanic leave a rag, either rayon or nylon material, down on my ceramic coated Hookers. The first time out in the car it melted and left a big dark stain on my header. I was very upset and went to talk to him and he agreed to make it right if the stain remained. I ran the car a few more time and the stain eventually just went away. It seemed to just burn off and now you can't even tell where it was. I would just drive the car for awhile and see what happens before you do anything.