remedy suggestions??

I have very dark skin between my thighs (including my 🐱)  and my armpits. It's been this way since I was about 14 (I'm going on 21 now). I am just curious if any of you lovely ladies have had this problem and if you have found any solution to get rid of or at least lessen the darkness. I'd like to add that this change is for me NOT for a man