Sexually transmitted diseases that cause pimple on vagina. Human papillomavirus [HPV] is a virus that cause genital herpes which forms bumps on the vagina. This disease does not cause outbreak when in it is initially contracted and can lie dormant for years before an outbreak is formed. Suffering from Vaginal Bumps or Genial Pimples? It could be symptom of STD. Read this page to find the causes of bumps in vagina or vulva. Sexually Transmitted diseases (more popularly called STDs) are diseases which are transmitted through the act of sexual intercourse. Vaginal pimples and acne bumps are common conditions on the external vaginal anatomy.. Genital pimples and acne can be on the butt cheeks, inner thighs and at the bottom of the vagina opening (labia).