Press Ctrl + Shift + N or go Layer > New > Layer to create a new Layer above your image layer. Press Ctrl + Alt + G to apply a Clipping Mask. Set the Layer Mode to Screen and Opacity to around 50 per cent.
Press Ctrl + D to reset your colours. Select the Gradient Tool G. Click on the Gradient in the Options bar to bring up the Gradient Editor dialog box. Select the default Foreground to Background preset. Drag the right marker, the white one, to a Location of 50 per cent. Click on the left marker, the black one, and then click on the Gradient to the far right. This will add another black marker. Drag your position stops in slightly towards the middle on both sides.
With your new Gradient selected, click and drag a small distance, from the top left to lower right, over the distorted corner of your image. You’ll want the gradient line to mark the bend of your sticker. It may take a few tries to get it perfect and this method of using the Gradient tool gives you a bit more flexibility.