I cannot confirm anything without examination but it can be due to hyperpigmentation skin. If it is raised plaque like lesions, then we need to rule out other possibilities. For the confirmation of the same, I suggest you to get an evaluation done from a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.