It's taking its final shape. There's a fixative spray that gently varnishes it. Perhaps it won't damage it:
Winsor & Newton ASFIX Artist Soft Fix Spray Fixative - Fixative spray to protect charcoal, colored pencil and pastel drawings, 400 ml: Amazon.es: Home and Kitchen https://share.google/bWjc1KZ5cEhNceUvB