I'd suggest skipping the whole shower approach. Get a couple or three towels, a basin of warm water and a washcloth, a nice new safety razor, and a thing of shaving cream. Hole up in your dorm room with the door locked. Apply nice warm water to the area with the washcloth, let it soak a bit so that the hair is soft. Then apply shaving cream and shave in, very easy and slow, from the outside to where you need the edge to be. Just take your time and remember that in 20 years this will be a funny story.