Will the dark areas of my underarms caused by pigmentation be lightened with a laser?

I get stressed every time I wear sleeveless clothes because of the darkened skin on my underarms. Even though I remove hair consistently, my skin itself looks dull and dark, which lowers my confidence. I haven't seen much effect from over-the-counter whitening creams, so after much deliberation, I am considering dermatological treatment. Is laser treatment to improve underarm pigmentation really effective? I would like to know how many sessions are required, and if there is any pain or precautions to take.