Your photo shows a small, flat, darker spot on the skin, which looks like a mark left behind after scratching or minor irritation, not an active rash or open sore.
Next Steps
Keep the area clean, avoid further scratching, and give it a couple of weeks; marks like this usually fade on their own as your skin heals.
Health Tips
Please see a gynaecologist or dermatologist if it grows, changes colour or shape, becomes painful, or doesn't fade within a few weeks.