I think his healing song (do you mind if I call it that?) may help her get two different regains depending on the situation. Like, for example, if he someday uses it on her while she is suffering from poison or illness, and if she witnesses him using it to heal others, then it'll remind her of having the ability to help people with her hypnotic songs.

Unfortunately she isn't much of an instrument person, but classical music could help her remember other details about her past. She was royalty and all, even if she didn't act like one. Plus, from your description of this character, I feel they would get along outside of the regains too. People with no shame and super chill are very much needed her life to be chill and do stupid stuff with.