How did the "terrible experience" related to "The Frost King" leave a lasting impression on her mind?

When Helen was summoned by the investigative body to answer on the charges of plagiarism, Keller was very disappointed. She found that irrespective of her explanations, the committee had already decided that Helen had copied the "Frost King" from Miss Margaret T. Canby's "Frost Fairies". This had frightened Keller so much that she refused to resume writing. Even while writing letters to her mother, she would double-check thetem to ensure that each an every word or expression was her own creation.