Hello,
When you say discoloration is it due to darkened skin or lightened skin? The differentials and treatment methods for both are different. So please describe the rash in detail.
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.