Our TG Caption

Now that only you and Pammie know what you look like, you are free to roam the halls without drawing further attention to yourself.

Using your heightened intellect, you deduce that Bonnie must have brought the lamp with her to school to keep you from getting it, yet she probably doesn't have it on her person, since she's distracted by her wish that let's her play around with you. You find Bonnie's locker and crack the lock. Sure enough, there's the lamp.