I know this is bad, BUT...
When I was younger and "scorched" something with the iron, if it was not too bad, my mother would re-wash it and it usually came out okay. But then again she was a heavy starch woman! I don't think I ever actually burnt through a shirt or whatever.
So, is there anyway that you can see if it is salvagable? Can you carefully wash the affected area and see if it will wash out?
Just wondering.
Good Luck & Happy Quilting
Susan