How do i know if i have herpes because i don't see blisters but i just itch monthly under clitoris hood where the hair grows it's really red and itchy?

Probably not herpes: Recurrent itching usually isn't herpes, and herpes rarely recurs as often as once a month; 3-6 times a year is more typical. This sounds more like a yeast infection or some other skin condition. See a doctor while you're having symptoms. Australia's sexual health centres are superb, and Melbourne's is among the best. Give them a call or see your personal physician. Good luck!