I am not entirely sure that your question is completely clear, but I will give you some ideas anyway and then hopefully you will be able to use those ideas to do what your teacher is expecting of you.
If I had to do something like this, I would probably want to write a poem based on the "character" if you can call it that of the woman that the narrator sees trapped in the wallpaper. Clearly, as readers we can understand that this woman is actually a representation of the way the narrator herself feels trapped and constrained by the restrictions of her husband and the doctors who advise him, and is emotionally and intellectually stifled. It would be really interesting however to give this alter ego a "voice" and allow her to express what the narrator perhaps isn't aware of, giving her the opportunity to share her pent up frustration and anger. A poem written from this perspective would be able to "see" what we as readers can see but what the narrator can't, making it a fascinating experience. Hope this helps and good luck!