Read this book in early 1990’s when I was a teen. A boy goes to a military type school and discovers a tunnel in a mountain with a small crystal like town and he pricks his finger on a fang buried in the ground end ends up in hospital.
Stump the Bookseller
New format, same book stumper solving.
Sounds like “Through the Hidden Door” by Rosemary Wells.
That is it!! Thank you!