Recurrent nevus is a melantic skin lesion which clinically resembles a superficial spreading melanoma at the site of a recent shave removal of a nevus. What happens is that melanocytes left behind in the wound regrow in an abnormal pattern. This is accompanied by scarring, inflammation, and blood vessel changes and this both the clinical and histologic impression of a melanoma.
I suggest you to get a biopsy skin done to confirm the diagnosis. I hope it helps. Take care and regards.