thank you for your time. I looked at it today and its lighter. I think its due to heat rash/chafing. Again thank you
The main sexually acquired cause that comes to mind is crab lice, which sometimes are accompanied by bluish or purple spots (called maculae ceruleae, literally "blue patches"). The lice and their nits (eggs) can be hard to see. However, they usually itch.
Otherwise, I can't speculate. You'll need to see a health care provider. In the meantime, I wouldn't worry; I doubt it's anything serious.
Good luck-- HHH, MD