When I was younger & started shaving, my armpits began getting dark. Being young, I didn't pay attention to it because I thought it wasn't a big deal. One day, as I was putting on deodorant, my mom told me, "your armpits are really dark." After that, I've always been embarrassed about wearing any spaghetti strap or shirt with no sleeves in general. This has also limited the type of dresses I'd wear. A few months back, I was at Walmart & an employee helped me find this product:

I had never heard of it but it had decent reviews online so I decided to give it a try. I put it on each night (I've missed a few) for about a month I'd say. It is now showing results but I'm still not there yet. I recommend this product for anyone with skin discoloration, i bought it for less than $5 at Walmart.

(Excuse my growing hairs). this arm in particular is darker than the other & needs more work on it.

Some people have also used it for under eye dark circles.

Update: yes I've tried exfoliating. I've tried many things before ever thinking of buying a product & no my underarm isn't lighter than the rest of me, that's my underarm, you can't see the rest of me.