Using Number Variables and States or Layers?

There could be numerous ways to do this.  One might be like this attached.  Have one "bar" where the stars are, and its state changes based on a Variable count.  +1 for correct, -1 for incorrect.

I have the bar blank as normal state, and then each star gets filled in state by state.  

Can get tricky this way if the user kept clicking YES on any give question as the "count" would keep having 1 added to it.

You might want instead to change the counting variable so that it is only adjusted when user clicks submit or next.

E.g.  I have it as "add 1 to StarCount (variable) when user clicks Yes button" & "subtract 1 to StarCount when user clicks NO button".

Better would be to "add 1 to StarCount when user clicks Submit/Next, IF YES Button=Selected"  & "subtract 1 to StarCount when user clicks Submit/Next, IF NO Button=Selected".