About low priority queue

A few months ago, I was getting into league, but I left a lot of games back then, getting me into the 20 minute low priority queue. I got out of that, and haven't really left any games since then. but recently, Playing at a friends house, I kept kicking a cord under the desk, restarting the computer, and making me re log. I have gotten back on every time, without rewards (which I think is kinda dumb not getting any xp). Finally, I rage quit a game because, 1: I just wasn't feeling that game, and 2: I was just really annoyed with how the game was going. I know that was wrong, but I got placed into another 20 minute low priority queue. I kinda deserve this, but it is annoying. I have not left many games since My first 20 minute leave buster, and I thought it would be lowered to at least 15 minutes queue. How long do you have to wait until your low priority queue goes back to 5 minutes when you get it?