All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If the project assigned to you by your manager is related to lottery or similar prohibited matters, then it is impermissible for you to work on it, and the money you earn from it is considered ill-gotten, regardless of the source of such earnings.
Therefore, you should inform your manager that you will not take on this project, and there is nothing wrong with taking on other lawful projects in your company.
Allah Knows best.