Thanks for writing. Your submission should not include any aspects of Lilly's branding.
Per the Official Rules:
"Excluding Submissions, all intellectual property related to this Competition, including but not limited to copyrighted material, trademarks, trade-names, logos, designs, promotional materials, web pages, source codes, drawings, illustrations, slogans and representations are owned or used under license by the Sponsor and/or the Administrator. All rights are reserved. Unauthorized copying or use of any copyrighted material or intellectual property without the express written consent of its owners is strictly prohibited. Any use in a Submission of Sponsor or Administrator intellectual property shall be solely to the extent provided for in these Official Rules."
Please let me know if you have additional questions. I am happy to assist you.