Pattern, place, and pace
Even without seeing the bug, three clues narrow it down: how many bites, where on your body, and how fast they appeared.
Medical disclaimer. This page is for general information only. It is not a medical diagnosis. If you have severe symptoms — trouble breathing, swelling of the face or throat, fast spreading redness, fever, severe pain, pus, or signs of infection — contact a doctor or your local emergency number.