Exfoliate! there's a nice round scrubbing tool.. I'm not sure if it's still considered a loofa but they carry them at Wal-Mart for I think $1.50... Exfoliating really helps and a good deodorant as the others recommended
Thanks Kitty and Cookie, I never really thought hormone imbalance could be the cause. I am going to look into that.
Okay, so it's a lot like what Candi said. Here's the thing though. If you shave rather than wax your under arms, you'll want to let your skin breathe for 10-20 minutes after your shower/bath before adding deodorant. This is because when you shave, you DO cut your skin (Although it's not always visible to the eye), and your pores are more open and so putting deodorant on immediately after can clog your pores, especially if it's not spray on deodorant. Exfoliate when you shower, and there's also some moisterizers you can buy to help with the clogging of pores. Hope this helps.
Oh! And be sure to watch your skin where you apply moisterizers or deodorants and exfoliate, because based on the PH balances, along with your skin, it could irritate your skin. Doing it too frequently will as well. So when you start, try only a couple times a week to make sure you don't have a bad reaction to whatever you decide to use. Everyone's skin is different, so just be aware of that.
Be careful with your shirts. Shirts that are a bit tight around armpit area van cause irritation, making them darker. Like everyone says, deodorant can play a major factor. Also, shaving can do so. there are at home remedies that you can search online to help.