Will laser treatment for pigmentation really make this go away?

Because I didn't have enough knowledge about skin care, I kept making the mistake of shaving my armpit hair with a disposable razor for a long time.
I think many people would agree, but I used a razor out of habit because it was the easiest and most convenient method without the pain of plucking or the anxiety of using hair removal cream.
But this method ultimately irritated my skin. Every time I shaved, I'd cut myself, and over time, red, inflamed patches would appear, eventually leaving unsightly, dark, discolored patches on both armpits.

It's my own flesh, and my usual behavior is so unnatural that it makes me feel unnatural in front of others.
Can areas like mine that were caused by shaving be treated with a pigmentation laser?

If treatment is possible, what type of pigmentation laser would be most effective?

And I have severe pigmentation, so I'm wondering how many treatments I need to get to lighten the pigmentation.
While receiving laser treatment for pigmentation, are there any special care measures I should take at home besides quitting shaving?
I need some advice to help me get out of this predicament.