The hymen is a subject that generates quite a bit of confusion
What is it?
The hymen is a piece of tissue that lines the vaginal opening. It has an opening that can be of any size—it can be thin or thick. It should have an opening—otherwise your menstrual blood cannot come out and an opening would need to be created. Typically, the hymen has an opening the size of your finger—or the size of a small tampon. It is normal for it to be uncomfortable to pass a tampon and it doesn't mean that your hymen is gone if you can.
The hymen and virginity
You often hear about the hymen breaking with first intercourse. It can happen, but if a woman is relaxed during intercourse and has good lubrication and she or her partner has tried to stretch the hymen with fingers, then it likely won't break. So, you can't tell if someone is a virgin if they have a hymen.
A vaginal exam and the hymen
You don't need a pap smear until three years after you become sexually active or at age 21. But if you are sexually active, your doctor will do one before you start on birth control. Your doctor will go through what will happen during your exam and if done gently, with a small speculum (which is inserted into the vagina to open it for the pap smear), then it won't tear your hymen. It's not a comfortable exam, but if done properly, will lessen your anxiety and discomfort.