Suggest Treatment For Dark Skin On Underarms And Pubic Area

hi im an indian , female 18 yrs old , and im having problems on my underarms and pubic area, its very dark and itchy around them and now i have started getting swelling kind like pimples . and i do use razor to remove hair and when i used it recently after a long time i has gotten worse and more dark . if you could tell me which medicine or ointment should i use, it would be a great help. please help!