I have the same problem. And mine gets completely irritated by sex and even assisted masturbation. If it is causing you discomfort, you can visit a doctor and ask about having some of the excess skin removed. It is normal to have some asymmetry with that skin.
Also, if it continues to get larger with time, you may want to consult with a gynecologist anyway. It's normal for them to get a bit more stretched out as you get older which can lead to discomfort in the future.