Changing formatting on review correct/incorrect layer of quiz

Not instantly, but, you could try using variables and additional layers, maybe?

Something like:

• Create 2 T/F var for each question, set to False, Add trigger on Correct and Incorrect layers to set the applicable var to True (say the variables are called q1_correct and q1_incorrect... on correct layer you would say "Adjust variable q1_correct to True when the timeline starts on this layer, and then the same on the Incorrect layer)
• Create two additional layers, one for correct review feedback and one for incorrect review feedback. Add whatever content you want on those.
• Then, add triggers on each Review layer: Show layer [correct review feedback] when the timeline starts on this layer IF variable q1_correct is equal to True.... and another saying Show layer [incorrect review feedback] when the timeline starts on this layer IF variable q1_incorrect is equal to True.

I have not tested this, but logically it should work, I think :)