Tricia, it is possible for the silks to turn to a purple colour (then brown) after pollination but if this is the only one and it is real purple it may be a different one, Kandy Korn for eg and some of the decorative ones have purple tassels, if this one really stands out I would get it out if not too late, if not it may pollinate with your others and spoil the lot..not easy to say, but maybe losing 1 plant is safer. Any chance of a quick picture?
XX Jeannine