I just won a game, but lost LP. Can I somehow get that lp back?

I had to leave for a few minutes at the beginning of the game because of my computer crashing and shutting down. Then I came back, and was forced to leave due to nothing dying or taking damage, so I left and came right back. We won the game, and I finished with a good score. But, the problem came afterwards, when it said victory, lost 17 lp. Ummmmm.... I won. Why did I lose lp? Nothing makes sense there, because I have seen people be afk for half the game still get lp, but I was there and lost lp. To top it off, I went to report a bug, and it doesn't load. So I have to do it here.