Insect bite;does not itch;day 1:quarter to half dollar bright red circle;day 2:bigger; day 7 redness is nickel sized and less bright. how much longer?

Couple days: If your bite looks like a target (like the picture), please see a doctor right away to get treated for Lyme disease. In general, insect bites last a week or two and get better without any treatment.

Insect bite: that it is getting smaller is a good sign. I assume no other symptoms? If not, also a good sign. Any other medical issues that may affect healing? Diabetes, blood vessel problems? If not, would expect resolution in another 3-4 weeks. If any issues that prolong healing, expect up to 2-3 months for healing. Hope this helps. Good luck