My professor wants proof that I ran the lesson. What can I do?

If your professor is using LessonLink and you correctly followed the special URL your professor provided to you, your professors will see your scores. They will not see a score from a lesson simply run by finding the title on the CALI website. You know your professor sees your score, if you see your professor's name in the appropriate column in your "My Lesson Runs" dashboard. If that column is blank for that lesson run, your professor does not see your score.

If your professor is not using LessonLink then your professor will not be able to see your score.

So, if the professor needs physical proof, then printing the certificate at the end of the lesson should suffice. If you have no access to a printer or your professor requires a digital printout over email you can do a basic screen capture or print to PDF.