In my last game, an unfortunate circumstance befell my character:
I was engaged with two ghosts, however, the "master" of the ghosts (who had been appearing and disappearing at random) had just reappeared in the middle of the room. He had taken a bit of a beating already, so I decided I would do my best to finish him off.
I managed to get in range to use my breath weapon (I am a Dragonborn), but, since I had been previously engaged, the two ghosts got opportunity attacks as I left their range.
2 natural d20s.
Needless to say, the damage dealt was more than my hit points could handle, so the DM struck a deal: he would let me make my attack, if I gave something to him in return. We eventually settled on a permanent injury, when my character regained consciousness.
So I looked around, did a bit of researching, and I'm not sure, but there doesn't appear to be any kind of injury system in 5e. Is that the case?