I have dark underarm and I been trying to clear it... my aunt told me to use lemon and rub it underarm but its taking so long to clean.. is there anything else I can use

lightening soap, vitamin E oil,and lightening tube cream, 3x daily for 4 weeks, then twice daily for 4 weeks, then once a day or a few times a week to maintain, since that spot doesn't really get much sun light.