Would skin bleaching improve the appearance of this problem?

So many years ago I was told I had acanthosis nigricans or hyperpigmentation. I was treated for the underlying problem which in my case was a thyroid condition. For a long time my skin was really good however about 2 years ago I had to stop taking my thyroid medication as I lost health insurance and couldn't afford medicine anymore. My skin was still relatively fine minus the condition coming back a bit on the top of my neck and underarms however very recently within the last 4 months or so it has come back worse(possibly from my birth control now?) and is quite annoying as although nobody else seems to notice much it still messes with my self esteem a bit. I know the only real way for it to go away is to treat what is actually wrong but I just thought since skin bleaching can help with dark spots, old acne scars, and evening skin tone maybe it could for this to.

So does anybody have any idea of this may or may not work?