Chloe's dorm-room typing. Voice-over: "Note to self: Never confront a vampire when they're [sic] hungry. Even if they [sic] are your best friend." Lana is Chloe's best friend? I find that sad and distressing.
Back to the party. Clark isn't wearing the mask. They called it The Mask of Zorro for a reason, numbnuts. Clark's vestigial super-hearing suddenly kicks into gear as he picks up Chloe grunting in pain. She calls Clark's name. Clark arrives just in time to see Lana sucking the neck out of Chloe. "Lana?" Clark asks as she turns to him with blood on her teeth. Chloe falls into Clark's arms as Lana sneers and backs away. Lightning flashes as Lana backs up onto the balcony. We see tooth marks on Chloe's neck. When Clark looks again, Lana's disappeared. Again, it's not like he has powers where he could follow her or x-ray her location. Because it would be cool if he could.
Commercials. Oh, Eva Longoria. From quick stardom to shampoo commercials already? Be a little unpredictable, why don't you?
Hospital. It's not Smallville Medical Center, at least. Chloe's got a clear bandage on her neck, the better to see the two big puncture marks through. Do they really treat a wound like that by sticking a small Zip-Loc back over it? A doctor tells Clark that he doesn't know what to do. Comforting! He says he's tried a blood transfusion, but that nothing's helping. Maybe we should call Chloe's dad. No? Bad idea? All right. Forget I suggested it. Clark asks what's wrong with Chloe. The doctor says that Chloe's been infected with a rabies-like virus; it's attacking Chloe's red blood cells. Those are the red ones, right? Doc says it's keeping her RBCs from regenerating. Red blood cells regenerate? I'm totally gonna go get me a wound! The doctor suggests continuing transfusions and hoping Chloe will stabilize. The closed captioning reads, "Paging Dr. Bender. Dr. Bender." Clark tells an unconscious Chloe that she has to fight this.