Skin

Skin by Koja, Kathe. hardcover edition. ISBN: 9780385308991.

As a sculptor of metal, Tess is consumed with the perfection of welds, the drip of liquid metal, addicted to the burn. Her solitary existence ends when she meets Bibi. A self-proclaimed "guerilla performance artist," Bibi pushes her body to the utmost in her dancing, sculpting it into a finely tuned machine. But the limits of her body frustrate her. With Tess, she creates a performance art of mobile, bladelike sculptures and human dance that becomes increasingly violent and dangerous. Still this is not enough for Bibi. Her desire to grow and transform leads her to body piercing, then to ritual cuttings and scarrings. And further. Though Tess breaks their partnership, she cannot stop Bibis dark exploration of the limits of her body. Her search is self-destructive, all-encompassing...unstoppable.