What Insect bite leaves a group of small blisters very itchy swelling and lots of oozing once they break?

Two answers come to mind, although many insects can do this. Try these: What you describe is exactly how poison ivy, poison oak, and poison sumac all present. Do a search on Poison Oak for detailed information. In the mean time, Don't Scratch! :} Chiggers are larval mites, family arachnidae, like ticks, Spiders and the like. They're bright red and, while visible to the naked eye (sometimes), they're about the size of the period at the end of this sentence. Chiggers prefer to feed on birds, but will accept humans. They'll head for warm country, so look at your ankles (if you were wearing socks), belt line, etc. They burrow a small hole through your skin, and inject digestive juices that dissolve your cells, which they sip as through a straw. After a while, your body catches on, and hardens the cells around the "tube" and eventually at the bottom, sealing this "soda straw" the chigger was using. So the chigger will move on and bore another hole. This goes on for about 4-5 hours if allowed, at which point the chigger is full, drops off, and never does this feeding trick again. Instead, they form a pupae, metamorph, and emerge as adult, vegetarian mites. The remaining tubes are what cause the itching. They're basically "splinters" of dead, irritating material that your body crafted to survive against breakdown. And they do, for about 9 days or so. And all during that time they itch. Ice packs, a mild analgesic and patience are about all you can do. You really shouldn't scratch Note that chiggers do not bore under the skin -- this is a pretty common wive's tale. You can get more info on this if you search under "Chiggers" on this service.