For the past 3 weeks I have been using a cheap deodorant (stupid decision, I know) that has caused minor rashes but nothing too serious. Now, I've noticed my arm pits are darker than usual. I've decided not to use this specific deodorant any longer. I've used deodorants all my life and never have I had this skin darkening problem. Is this permanent or will it go away on it's own? I am 20 years old, 5'8, weigh 140lbs, male with no known medical issues. Thank you.