It’s possible your laptop has got stuck when trying to lock or unlock itself - hold the power button on your laptop button down for around 30 seconds to force the power off, then turn your laptop back on and it should be fine.
Please keep in mind it may ask you to swipe down, or may flicker black for a moment - disregard this as it may not be fully shut down and continue to hold it past that point until you're confident it has been fully powered down.