Having returned to the Gryffindor common room and gotten himself ready for bed, Harry was sat in his four-poster bed contemplating the dittany extract, and the ointment that Snape had provided him with - in particular, the dittany, remembering how much it had burned on application, and the awkward angle Harry had had to tilt his head at for Snape to administer it. He was not particularly confident he’d be able to do it on his own, but he had to at least try he guessed.