Drells solution...

"Okay." said Drell eventually, "I think we're ready here!"
"So how is this going to work?" asked Zelda.
"Well, Sabrina is the only one who can save herself from the power of the Warcock. She must find it within herself to throw off his control and rid herself of his influence!"
"In English please Drell." said Hilda.
"I shall shrink her down to microscopic size, then Sabrina must travel through her body and kick the Warcock babies butt!" clarified Drell, "Of course, her bodys natural defenses will see her as an invader and try to protect the baby."
"And this is the ONLY way?" asked Zelda.
"Yup! Here we go!". Drell began to wave his hands mystically over Sabrina head. Nothing seemed to be happening.
"Ahem, Drell?!" sighed Hilda.
"Quiet!" he commanded, then squarely flicked Sabrina on the nose. At this there was a popping sound and Sabrinas head began to shrink accompanied by the sound of a deflating balloon. Smaller and smaller it shrank until it disappeared from view...

Sabrina fell with a splutch into a puddle of ichor!
"EEWWW!!" she moaned, "Thats so gross! Now, where am I?". She found herself in a largish 'room' with red veiny walls.
"You know what to do!" echoed a voice that sounded Drells. Sabrina looked up and saw the tiny hole where her head had been. Just visible outside were the huge and worried faces of her Aunts and Drell.
"Right!" she replied. She was a little surprised though, she had a body 'inside' her body and her head was perfectly clear. No trace of the Warcocks addiction.
"Be careful!" called Zelda. Sabrina looked about. There were several 'exits' which looked like meaty tubes... Obviously veins. Picking one she set off.