Why did my wound turn black?

Patient: Three months ago, my dermatologist surgically removed a wart from my ankle. I had a typical wound after it was removed with a normal, red scab. I applied Vaseline and a bandaid for 8 weeks. After that time, I noticed the scab was no longer typical and rough, it was starting to smooth out and turn a darker color. It has looked the same way for over a month with no sign of progression. The site of the wound is black, shiny, and raised. It gets flaky and itchy if I do not apply hydration.

Symptoms: Only very slight itching if the area is dry.