Nena let out a strange sound as she hit the man, something like triumph, mixed with a sneeze. However, she was distracted by a notification super-imposed into her vision, announcing that she had turned orange. This, of coirse, was a shock since she liked her normal colour, and so she didn't notice getting headbutted until she had actually been headbutted, and then with his boot getting stuck in, she was knocked back, granting distance for both of them. Nena let out a cry of pain as she was headbutted, and staggered for a few seconds before regaining her footing. 
"Ow!....hey, your head thing is Orange now. I wonder if that is what that notice meant...." Nena put in, pointing tothe diamond like shape that hung over everyone's head, usually green, but now orange, and ominous for those who knew what it meant.