I have bad itching around my vulva, exterior vagina, and onto my inner thighs. i am noticing some swelling and what may be a pink/red rash. i have tried using cortisone cream for a few days, but the itching has persisted. what treatment should i try?

OTC products are less likely effective for your condition. If you have recently used a new soap for your genital area or you use new underwear, get rid of them. Avoid scratching, keep that area dry and open, apply lidocaine cream or ointment 4% OTC on those areas as often as needed for controlling the itch. If symptoms (rash & itching) do not improve after 3 days, see a dermatologist.

The most common cause of vulvar itching and rash, especially spreading onto the thighs, is yeast (candida) infection. Cortisone cream inhibit the immune system against candida, often making symptoms worse. See a doctor for diagnosis and proper treatment, probably with one of the many "azole" vaginal creams or oral medication (fluconazole). Good luck.