My mom had basal cell carcinoma that grew beneath the side of her finger nail causing her nail to rise as the cancer grew. She ended up needing 3 additional surgeries after her first doctor left her finger cut open to the bone for four days (#2 to correct the first surgeon’s mistakes/remove additional cancerous cells that were missed, #3 to use a skin graft/ sew her pointer finger and middle finger together, #4 to cut them apart about a month or so later). Her original doctor said that he had left some of her lunula/matrix in hopes of a new nail growing back afterwards. Surprisingly, her nail grew back perfectly and you wouldn’t be able to tell that she’d ever had surgery. My aunt has had the same cancer in 6 of her finger tips and has had similar luck with her nails growing back, although her doctors have usually cut her finger down the center, leaving half of the original nail to create a path for the new nail to grow into. My mom’s entire nail and about 1cm of her finger tip were removed and her nail grew back much better than my aunt’s did since she has a ridge where they cut her finger down the center.