Julia

The other day, Julia went out with Emily and Katherine to play in the yard. She came in with a couple of "bug bites" on the back of her neck, right at the hairline. They were small, with a dark red dot in the center, and a pink circle around. She had an other one, just a little further down on her back, but it looked more like a mosquito bite, as it did not have the red dot in the center. I thought nothing of this at first, but the next day she went out, and came back in with a few more spots on her back, one on her upper chest in the front, and one one her face, next to her left eye. The older girls were fine, not a single mark on them anywhere. They were all in the sandbox so I just thought it was weird that if it was bugs biting, they would only attack Julia. I was (am) beginning to wonder if it might be something else. Today will be a good test as I do not plan on sending her out (it's raining) and, after giving her a once over this morning, I do not see any new spots. They appear to be itchy, as she keeps asking me to scratch her back for her.

Anyway, just in case it did turn out to be something other than bug bites of some sort, I took pictures. Does anyone have any thoughts on what these could be?
(click to enlarge images)
These are the ones on her neck, taken shortly after she came in. the one below it was the one I was referring to that look more like a mosquito bite.

This one here is on her back, but is missing the pinkish ring that the others had.

This is the one near her eye, taken this morning.

And this is what her back looks like this morning.