Your SPOT should start purple, showing you the color you'd see when you're not protected.If you've followed the directions and your SPOT is still clear, check the following:Make sure that you've applied enough sunscreen to your SPOT. Allow the sunscreen to soak into the SPOT before rubbing in completely. You might learn that you haven't been using enough sunscreen. On average, people will use only 25% the amount of sunscreen required to get the advertised SPF on the bottle. Make sure that your SPOT and sunscreen are exposed to direct sunlight. SPOTMYUV requires sunlight to change color. While SPOTs will eventually change color indoors or in the shade, the change will take MUCH longer without direct sunlight.Avoid touching SPOT after sunscreen has been applied. Continuous rubbing will remove sunscreen.