Can you find another way to send pics? The thing is, the spot, or spots, can be completely benign or can be dangerous skin infection(s). In the meantime I would gently scrub the spot with warm soapy water, then start putting Bacitracin (Bactracin?) on the spot(s) in the mornings, and an OTC antifungal ointment in the evenings.
If the spots are tiny, they could be new, black scales growing in. That is normal as the iguana grows. They have smooth edges and have the shape of a normal scale. Can you find or borrow a loupe to get a good look?