I spent hours adding general comments to a quiz after the quiz had been taken, in order to address common issues students had so I wouldn't need to leave as much individual feedback.

Big mistake. Apparently, general comments won't show up if you add them after a student has taken the exam, unless you regrade the question. And most questions in my exam can't be regraded, plus the "regrade" notification would only be confusing to students.

Is there any way to get general comments or anything all students can see with their exam to show up if you add them AFTER the quiz has been taken? How?