What is it when you hymen is swollen no itching no pain no discharge

How do you know your hymen is swollen?

Nicole, it would be helpful if you gave more information.

How long has the swelling been occurring?
Are you sexually active (including oral and hand)?
Has anything been inserted into your vagina including fingers, toys, tampons, etc.
Is it your hymen (the ring of flesh inside the vagina) or your vulva (the external sexual organs at the opening of the vagina) that is swollen? Have you recently had a gynecological exam?
Have you recently changed laundry detergents or bath/beauty products?

Have you been extremely aroused? Females experience 'engorgement' (increased blood flow) of the sexual organs when aroused.