Refresh me on how MMR works
So to give you guys some context, I am in plat 5, and I was plat 4 a couple months ago, but I broke my hand and couldn't play, so I let my account decay to gold 1. When I got back I quickly got a promo and got back to plat. From there on, I've had ridiculously bad MMR. I haven't been doing spectacular, but I certainly haven't lost more than I've won since I came back. Regardless, I am gaining 15 lp per win and losing 23. Why? I haven't been doing that bad. I've had lose streaks but I've also had win streaks. Recently I won 6 games in a row, all for 14-15 lp, lose one, and lose 23 lp. Could someone explain how the system works to me, and why my MMR is so terrible? Also, could someone tell me what I have to do to break the trend/raise my MMR? like...should I get myself to gold 3 so I can win some and maybe get my MMR proportionate again? I just ask because I've not only gotten to promos but would have on many other occasions if I just didn't lose so much lp per loss, and it's REALLY frustrating.