The only reason I think it could be Lisbon, is the last 2 killings. The faces in both were very different from the previous ones. The faces are usually cleanly drawn, in one stroke. The last 2 were shabby, to say the least, and with multiple strokes. Which is what would happen if the killer had an injured hand (season 5 finale). I don't see any other reason for the injury being shown in the episode, as it had no other consequence.
