Show Next Button After completing an activity on a different site

I am looking for a way to only show the next button after the user clickers on a button.  Sounds easy right, but in this case after clicking on the button, the user is placed into a virtual learning game that has been developed in unity.  After completing the game, it redirects back to the slide.  However, it appears that when the user is brought back to the slide all of the variables have been rest. ie. it doesn't remember that the user has already clicked the button, and the next button remains hidden.