I believe this is a misreading; Winky was there, but the Dark Mark was cast by Barry Crouch Jr. From the climax of Book 4, towards the end of Chapter 35:

I wanted to attack them for their disloyalty to my master. My father had left the tent; he had gone to free the Muggles. Winky was afraid to see me so angry. She used her own brand of magic to bind me to her. She pulled me from the tent, pulled me into the forest, away from the Death Eaters. I tried to hold her back. I wanted to return to the campsite. I wanted to show those Death Eaters what loyalty to the Dark Lord meant, and to punish them for their lack of it. I used the stolen wand to cast the Dark Mark into the sky.