What Causes A Feel Of Heat Outside Left Labia?

I am 42 year old female who's started perimenopause about 12 months ago. I take Estroven daily. I noticed several months ago (8) that I was experiencing what I describe as 'heat on the outside left labia' from time to time. The heat has picked up frequency from 1-4 times a month to 1-4 times per week. Is this part of perimenopause or something different?