 Lash aids Harry significantly in the final battle of "White Night", but when he regains consciousness he finds Lash apparently gone and (as Bob put it) deconstructed.Her final act was to commit a sort of suicide by redirecting a mental assault on Harry's mind to the otherwise unused areas of Harry's brain/subconscious where she resided.As a consequence, Harry became apparently free of Lash/Lasciel's influence; the sigil on his hand faded, and he dug up the coin (which still contains the true Lasciel) and turned it over to Father Forthill and the church for safekeeping.