"If you need to wash it frequently, because of potion fumes, then you should be using something very mild," Marietta told him. She reached out to take the shampoo bottles from his hands and looked at each of them briefly. "Most of these are too harsh to use everyday. They can be very good if you wash your hair every other day, but it sounds like your scalp is quite sensitive and overreacts to being washed."
Marietta placed each of the bottles on the table next to her. "Do you mind if I take a look?" she asked hesitantly. It was unlikely he was going to say no, if he had come here for help, but she felt struck by how strange it was to have your hands in your former professor's hair. Talking about it was easier, at least for a Ravenclaw. They might as well be talking about a book.