Shave vs punch biopsy

I received a very concerning biopsy last week referring to "lentiginous junctional nevus with severe melanocytic dysplasia". I had assumed the dermatologist took a punch but just learned today that it was a shave biopsy. Should I be concerned that a shave biopsy might not capture the necessary tissue? The microscopic narration indicated "no significant migration of melanocytes into higher epidermal levels". I'm not sure what that means...
Thank you.