Dark Bikini Line and Inner Thighs - what Skin Lightening can I do? (photos)

I haven’t been diagnosed with a hormonal imbalance problem, but my periods was never regular and I experience heavy bleeding. I am also around 45-50kgs. Since I was 12 years old, I’ll get inner thigh rashes and scratch it. I was clueless it would get dark. Until now, I haven’t been able to resolve this problem. What methods and procedures can I do? For now, what creams or serums I could put before getting it lasered? Thank you so much!