Simply put, hives are itchy welts on the skin. They can show up anywhere on the skin and vary a lot in size, from the size of pen tips to that of platters. Multiple hives can also connect on the skin to make bigger welts.
Usually hives disappear in about 24 hours and new ones might show up. This is how they can persist for some days. Nevertheless, one bout of hives does not carry on for more than 6 weeks. The medical community calls them acute hives. On the other hand, chronic hives are the ones that carry on after the 6 week mark.
The medical community refers to hives as urticarial. As these welts start appearing more deep under the skin, they are then called angioedema by the medical community. The same might happen with regards to hives and it leads to the eyelids and lips swelling up.