Can't quite get my head around this, at first it is as you say, but looking at it again.
How do we know how he got the injured mouth in the first place?
Had he previously been in a confrontation with someone in the first place, and then mugged that person and placed the items he took off his victim in his own back pack?
The guy or his friends then caught up with him and then took the items back, the only thing I can't understand is why he then threw them away?
What do others think?