Measle Bag (Last Remaining Originals)

Comedy, crowd interactive trick for children, with a surprise ending!

A red, and white handkerchief change color inside the bag... red to white, and white to red!  But wait, spots will appear!  Red spots on red, white on white!  But wait... now they jump... red on white, and white on red!  And finally a red spot is missing... oh no!  They're all over Johnny's face!  He has the measles! Bag turned inside out with a picture of Johnny with the measles.