Hi, depending on the amount of damage caused by the iron i would suggest:
1, Try "picking out" the burnt ends and cutting them carefuly with nail scissors or a razor blade.
2, Heat up a saucepan with white vinegar and plenty of salt. Rub the mixture into the damaged area quite firmly but without damaging the carpet further.
3, If these 2 methods fail you may consider patching the damaged area with a spare piece of carpet and trimming it in.
scratchmasters.co.uk, March 2009