[John gestures to his knees, where what little moonlight there is is just enough to show that his trousers have ripped and his skin is a little reddened and scuffed.]

I'm sure that's it, and I know I didn't get it from the rat.

[He narrows his eyes, having noticed Sherlock draw his coat closer.]

Show me. Your definition of 'just a scratch' and mine might not be the same. Hell, that thing might have even had poisoned claws! Let me see.