It can be improved with specific medicine...Undergo glutathione therapy.. otherwise few creams also available...for detailed prescription do direct online consultation by sending photos.

Hi underarms are usually dark due to ingrown hair as well as due to prolong fungal infection in case of hormonal abnormalities also there are high chances that you get such dark patches on your axilla that is your under arms aka acanthosis nigricans where you are getting dark velvety patch if you are having even associated with skin or any abnormal or irregular menstrual cycle Specific medications containing glycolic acid lactic acid urea could be helpful but it would be much better if you consult a dermatologist for the scene even if you have a sensitive and dry skin the treatment protocol changes accordingly