Does hives really last for more than one week in some people?

Depends on cause. Most commonly hives are short lived, but sometimes hives can last a long time and be resistant to treatment. There is an entity called cholinergic urticaria, which are hives from stress, emotional states, heat, and sometimes unknown causes. That can be very tough to treat sometimes and keeps reoccurring. Talk to your doctor, maybe an allergist, if your having hives for a long time.