Make sure you see a dr to rule out infection.
If not infection, it may be due to chronic irritation. First, practice good hygiene. Wash your external genital area gently with mild, unscented soap & water during showers, & avoid douching
or bubble baths. Avoid tight-fitting underwear (cotton is best) or unnecessary use of pads/panty liners. You might also try over-the-counter 1% Hydrocortisone cream
Answer assisted by Brittany Chan, Medical Student