Hives

Has anyone heard of hives originating from some sort of spider or other insect bites? In March, I had 2 insect bites, in similar locations behind each knee, about a week apart. By the time I got my sweats off, I couldn’t find the insect, but the bite marks were visible each time, and they each turned into circular, hard, black & blue bruises, about the size of a baseball. Within a few weeks, I had an outbreak of hives, but at first thought some other kind of little insect had gotten into my clothes. Later I started having localized swelling, on my face, (When my upper lip swelled, I looked like someone from Whoville in How the Grinch stole Christmas) , arms, back of my hand, and top of my feet. Some of it seems to be caused by pressure, as I get welts around my waistline from pants. I am about to go to an allergist, but have read a lot on the internet, and want to learn as much as I can. If any of you have had similar experiences, I would love to hear about it.