League is holding my laptop hostage/unable to log on to my laptop because of League

I recently just got a new Macbook. It is a Macbook Pro. I installed League on it to play since it seemed to run it better than my old desktop. While in a game, the battery died, leaving me AFK. After a few hours, I got back on to see that my mouse was the in-game League mouse on my lockscreen. It is making a few sounds from the game (Which ended, so not sure what sound it is displaying) and I am unable to type in my password or move my mouse. Even after trying to close and open my laptop numerous times, it still remains this way. Stuck, displaying my lockscreen. With the help with my brother, I was able to log in onto my account and try to mess around with the settings and everything, get into a game, and still nothing worked. I'm not sure if this is common, as I am very unfamiliar with Apple products, but any help would be much appreciated. This all happened today, and I want to see if I can fix this at home before seeking proper help. Thanks in advance.