Many safe, effective home remedies can reduce or eliminate underarm discoloration in a matter of weeks:
-Wax or pluck the hair under your arms instead of shaving with a razor
-Consider changing your antiperspirant/deodorant,try using natural deodorants instead,
-try applying organic talcum powders to your underarms instead of antiperspirants and deodorants.
-Avoid wearing tight, ill-fitting clothing
-Exfoliate (scrub) the skin under your arms with a gentle exfoliating cleanser and loofah several times per week.
-Use lemon to treat underarm discoloration. Fresh lemon is one of the most effective ways to lighten underarms. Cut a lemon in half and thoroughly rub the lemon into your armpits
-massage your underarms with vitamin E oil, potato oil, or coconut oil daily. These oils contain natural bleaching properties
-If you're looking for more immediate results,you can go to the doctor or dermatologist to prescribe a bleaching agent or recommend an over-the-counter one some medications ,Dermabrasion, which uses a rapidly rotating device to abrade the surface of the skin, and laser therapy, which burns off skin imperfections with a laser beam, are effective remedies for darkened skin