Lock Screen

So today, I played a game of Draven, and I accidentally pressed a button and it caused my screen to lock. I asked my team what button I had to press in order to unlock it and they said "Y". I pressed y and it didn't do anything. I also tried to click/drag on the minimap and click the small camera button on the bottom right of the screen, but nothing happened. I reset to default, and tried the same things again, yet to no avail. Eventually the Taliyah on my team told me to disconnect and reconnect (which worked), but by then I was several levels under everyone else. By the time I could reconnect I was so behind we just lost an easy game. Good thing this happened in a normal game, so I now know not to try playing ranked again until this bug is resolved.