I'd be grateful if anyone could tell me what these marks in the navy field (lower right) are likely to be.
Thank you!

This old Ardakan has lost a lot of pile in the years. As the pile gets lower, some white knots show all over the rug. These knots are where the cotton warp or weft had to be knotted together because the string ended and a new string had to be knotted together with the old string. In the place where this knot is, there can be no knot made of wool since this place is already taken. These white knots are not visible as long as the rug is new and the pile is high. After years of use the pile gets shorter, and the knots show. What you see on the picture is the ususal way of "fixing": just painting the knots in the color of the surrounding wool. It is no damage, it is the usual way of making an old rug look better. Just compare it with make up for women. It depends on how professional it is made to look good or not. The work on the picture was probably made by a "male make up artist" :-).