Hello and welcome to the forum. Thank you for your question! It's always best to speak to your doctor about this as they are the best to guide your personal situation. I would agree with your thoughts that this sounds like a pigmentation issue. Post inflammatory hyperpigmentation is the correct term and shaving a specific area can indeed result in this. There are some natural things you can try. This article has a long list of natural remedies. https://www.healthline.com/health/home-remedies-for-pigmentation Aloe vera, green tea extract, apple cider vinegar, and milk are some of my favorites. There are also treatments a doctor can provide that will likely work faster. Chemical peels or laser derma resurfacing , for example.