Tiny pinprick sore on labia major that comes/goes in exact same spot, bleeds a tiny amt. Not STD. I noticed it comes around the same time every month?

Herpes? Any lumps, bumps or blisters on the genitalia require an exam to visualize the abnormality and determine the cause, tests or treatments. A recurring lesion in the same spot in a cyclic pattern is concerning for genital herpes. Testing can be done.