As Katie pulled Tiffany briskly along, Tiff reached up to the empty area where she used to have a head. Katie's "examination" had made her horny, and her deprivation of all other senses amplified her hungry sense of touch. She began massaging the flat skin between her shoulders, and to her surprise it seemed to function as an erogenous zone. She trusted giving Katie complete control over her, because she was in no position to resist her like this, in the middle of the greatest self pleasuring of her life.
Katie was poring over rows and rows of vaguely labelled bottles, hoping to find something that indicated a head restoration. She was trying to read the faded label of a small jar with an image of a neck on it when she noticed Tiffany's body convulsing and her pants developing a light stain around her pussy.
"Cut that out Tiff, you'll have planty of time for that later. Besides, we don't know who could see you here."
She held out the jar to Tiffany. "We're going to try and restore your head. I don't know what kind of magic in here is keeping you alive, but we're going to have to get you back to normal before we leave."
Tiffany pushed the jar away, before returning her hands to her neck and pussy, where they were hard at work.
"Tiffany! Alright, I'm giving you this potion whether you like it or not!"
She pulled Tiffany's hand away from her headless shoulders and poured the meagre contents of the jar onto Tiffany, absorbing it into her skin. At first, nothing happened, then a lump started to form between her shoulders.
"Ok Tiff, we'll get your head back, then we'll be out of here in no time. I can't wait to get out of this dump."
Tiffany's neck started to grow up out of the skin between her shoulders. It slowly extended outwards, until it was several inches tall.
"Wow, it's really working! Wait- why is it slowing down?"
Her neck's growth slowed to a crawl before ending in a flat layer of skin, just shy of where her head should start. Tiffany's body looked somewhat relieved as she proceeded to explore her new extended neck.
"Dammit! I should have known by looking at the bottle. Well, at least we're halfway there now." Katie sighed, before returning her gaze to the medicine vials, as the headless Tiff resumed her newly enhanced masturbation session.