What you experience appears to be a problem with the display of the phone. If the screen is white and stays like that, then you will have to visit your local support shop to perform diagnostics. However, try restarting the phone by pressing the Power button for a long time until it turns off automatically, then turn it back on. If it has the same behavior, warranty service is necessary.
In case if the phone starts working normally, access Play Store and install an antivirus.
