It may be remnants of an old shed, but she may have somehow pulled a "current" scale up. Sometimes in their wanderings and explorations, snakes will catch a scale on something. If that's the case, just leave it be. Keep an eye on the area next shed, in any case.
If you're really concerned, you can put a tiny dab of A & D Ointment on the spot. That will provide some moisture as well as a modicum of a barrier to infection. I wouldn't mess with the scale too much, apart from putting some A & D on it. Most snakes are understandably sensitive about having their heads handled. There's no cause to stress anybody out.