my 525 has 3 three tiny white dead pixels.i have can hardly see them.they dont bother me but at very low light places they are visible but hard to see.i went to nokia care they told me this normal for all phones is that true???? they told they wont replace the screen for 3 tiny dead pixels.but i have seller's replacement should i replace my phone.will the rate of dead pixels increase by time or will it cause serious trouble i m very worried for it please help