The dark discolorations on your inner thighs could be a genetic factor, or may be caused by friction. Please try to consult with a dermatologist for a treatment option that's right for you. If you're too shy to see a doctor, there are over-the-counter skin lightening creams that may help fade them. Look for a cream containing kojic acid, glycolic acid, or 2% hydroquinone. These ingredients are known to lighten skin discolorations. Apply the cream to the dark areas twice a day for 1-3 months for results.