Hello and welcome to healthcare magic I would keep a possibility of Acanthosis Nigricans. Acanthosis nigricans is a skin disorder in which there is darker, thick, velvety skin in body folds and creases. Acanthosis nigricans usually appears slowly and doesn t cause any symptoms other than skin changes. The majority of cases of acanthosis nigricans are associated with obesity and otherwise idiopathic. This is likely because of insulin resistance, and more likely to occur in darker-skinned persons. This is also known as Pseudo-Acanthosis Nigricans. Acanthosis nigricans is likely to improve in circumstances where a known cause is removed. For example, obesity-related acanthosis nigricans will improve with weight loss. People with acanthosis nigricans in general should be screened for diabetes. Weight loss and controlling blood glucose levels through exercise and diet often improves symptoms. Topical tretinoin 0.05% cream once daily at night helps to lighten pigmentation along with weight loss, exercise and diet management. Alpha-Lipoic acid ha been shown to increase insulin sensitivity and thereby reverses the pseudo-acanthosis nigricans which arises as a result of insulin resistance states e.g Obesity and diabetes. It is commercially available for prescription in acanthosis nigricans. I would advice that you see a dermatologist for a confirmatory diagnosis. take care regards