I placed the sticker over the speaker on my tummy for 20-30mins when I received it. The next day I noticed the area where I had the speaker was red, itchy and irritated. Over the past week the redness faded and the itching stopped, however I am now left with this dark area on my belly that's taking a while to go away. The picture was taken 1 and 1/2 after I used it. I will be returning the product.