This is a common problem as the vulva is a sensitive area which is exposed to various things, e.g. urine, blood which may irritate it.
Vulval eczema may be associated with eczema elsewhere or may occur on its own. It may be precipitated by an episode of thrush or a reaction to a cream or the wearing of tight clothing which has caused friction.
Vulval eczema usually improves but the skin is going to be more sensitive for a few months and may react to things that previously did not cause a problem.
The following measures should help: