TMI: identify this bite?..

so about a week ago I was wearing shorts and going through the woods exploring. I was out there for hours running into many different things, but never felt a bite mark.. I live in the Southeastern part of the United states. I had the normal mosquitos, nats, and went through many spiderwebs. I did not locate any ticks on my body and these bites didn't seem to appear (or I didn't notice them till a day or so later... They keep getting bigger and the itch is almost non stop... What is this from? And how can I treat it?