Hello,
Welcome to healthcare magic.
I understand from your query that you are concerned about the darkness in your folds.
From your description, I would consider the possibilities of
frictional melanosis and
acanthosis nigricans.
Frictional melanosis occurs due to constant friction in the folds like underarms, below the breasts and groin folds. It is usually seen in individuals who are overweight. Weight reduction is an important step in treatment to prevent friction, rubbing and thus pigmentation.
Acanthosis nigricans is seen in individuals with a family history of diabetes and also in overweight individuals. You need a get a blood test done to check your sugars and insulin levels.
To lighten the area, you could follow the following suggestions-
1. Weight reduction if overweight.
2. Use a lightening cream containing kojic acid, arbutin, tetrahydrocoumarin and liquorice at bedtime.
3. You could get
chemical peels like TCA peels/ retinol peels done by a
dermatologist.
4. You could try oral glutathione and
alpha lipoic acid prescribed by a dermatologist.
Hope this helps you.
Take care.