In the past couple of days, your Surface Pro 4 likely installed a new set of driver updates known as “Surface - System - 7/21/2017 12:00:00 AM - 220.127.116.11.” Many Surface Pro 4 owners now report that after installing that driver, their camera refuses to log in with Windows Hello. Microsoft hasn’t yet responded, but a user has come up with a fix that seems to work most of the time—manually uninstall the driver.
Meanwhile, SP4 screen flicker and shaking is an older problem, first reported early this year. It, too, has not been acknowledged by Microsoft and has not been fixed. There’s no known workaround, but overheating seems to be part of the cause.