Inner thigh darkness: is this hyperpigmentation or acanthosis nigricans? (Photo)

Hi, I’m a25 YO female and I’ve had dark inner thighs ever since I could remember. Been using hydroquinone4% for about a month now but not seeing any visibly different results. Could this be just hyperpigmentation or acanthosis nigricans? Are there any treatments I could use to get rid of this? I’m willing to pay any amount to get rid of it. This issue has been crushing my self confidence for the longest time, I still have never worn a bathing suit to the beach. Thanks for your time