Good afternoon dimas193,
Welcome to the Apple Support Communities!
I understand you are having an issue with the display on an iPhone you purchased two weeks ago. Which iPhone did you purchase and what iOS software is currently running on it? Is the blinking happening in one app, or in all apps? I'll include a few general resources here to address this issue. If this iPhone was purchased from Apple, or from an authorized reseller, be sure to contact them if you are still within the period outlined in the return policy.
If the screen isn’t working on your iPhone or iPad
If your iPhone, iPad, or iPod touch won't turn on or is frozen
Shopping Help - Returns & Refunds
Take care.