Storyline Quiz - Hide (by choice) answer feedback on first run but appear on retry?

For Storyline questions, the feedback layers are either turned on or turned off. That functionality can't be changed based on whether it's the first run of the quiz or not. 

However, you can control what happens on the feedback layers. Here's how:

Create a T/F variable (default value = False) to track whether the user is repeating the quiz.

On all the feedback layers, use triggers that perform a desired action with the condition that the variable = False. As needed, add an Else statement for what should happen when the variable = True.

• For example, you could have the layer automatically jump to the next slide if the variable = False. Or you could use different states for the feedback text boxes when the variable = False vs. when the variable = True. 

On the Results slide, put a trigger that adjusts the variable to True when the timeline starts.  

It’s worth the effort to learn about variables and trigger conditions, because they provide the real power in Storyline. Here’s more information:

This post provides an overview of variables. It also links to numerous resources.  The Value of Variables | Articulate - Community 

The User Guide articles about triggers include some about conditions.  Storyline 360: Working with Triggers | Articulate - Community