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My phones upper clear touch area and the white light (digitizer) have been separated. I tried sticking them using double sided tape on the sides, using clear tape on the back of the LCD, super gluing the top area etc. Because of this the LCD has dirt on it. On the other hand the phone has no real damage and works fine. What exactly should I do. The LCD and digitiser have been separated, please help fix this mess. The screen and all work perfectly.

As the display is only 30 dollars I would replace the whole unit This guide will help Sony Xperia Z3 LCD & Digitizer Replacement If however you want to reuse what you have . Separate the glass from the LCD and clean them both completely so that you can stick them together.this will help with that Use distilled water to clean the screen with a microfiber cloth. Hope this helps