Xperia Z3 screen problem

[Matiya12]

The phone was purchased in November 2014 Pre 15-20 days, showed me the yellow stain in the upper left corner of the screen, best visible on a white background. Phone no physical damage, they did not fall, no scratches. Can someone help me and explain what could happen?Thanx
The display operates normally, as well as phone, I have no problem 

T

[Hampus]

Hi and welcome to the community! Since you're new please be sure that you have checked out our Discussion guidelines.

That does not look right. It's hard to say from here what the cause can be, I suggest that you visit nearest service center to have the phone examined by a technician. You can contact your local support team for information about nearest service center and/or how to proceed with this in the best possible way:
http://support.sonymobile.com/global-en/contactUs/

[Matiya12]

That is a problem...I`m from Serbia,my country is not listed...thats  why I ask for help .

[Hampus]

You can always send an email to your local support team to see if they can assist you:
questions.rs@support.sonymobile.com

Otherwise, you may contact your retailer to see if they can assist you in this matter.