Itchy, swollen, sore vagina and itchy anus. could it be infection?

Yes & no: Common yeast infections can cause your symptoms but so can more serious skin disorders. You must get an examination if topical antifungal treatment doesn't resolve the problem.

It may be: This rash needs to be visualized & a history needs to be obtained in order to make an accurate diagnosis. Sometimes lab testing or biopsy is necessary.