Go to the Hospital Wing.

Madame Pomfrey heals you quickly. You sit on a bed, eating a recommended dose of chocolate, already feeling better. As you make to leave, Neville Longbottom hops into the Hospital Wing. By the way he's walking you can tell that he has been hit by some sort of curse. Madame Pomfrey hurries out of her office, and with a wave of her wand, heals him. Neville slumps down on the bed next to you.