Could a laceration to the vagina of a 13 year old cause labial adhesion?

Yes: A laceration could cause labial adhesions but this can also occur spontaneously in young girls and not be associated with trauma. It is usually treated with estrogen. Do not forcefully pull it apart as this is very painful and could cause additional scarring. Although this is generally an easy problem to care for she should see a doctor.

Vaginal lacerations: My first concern would be why does a 13 y/o have lacerations in her vagina. Only then could i begin to formulate a response to your question.

Yes possibly : It depends on the location of the laceration, how it was surgically repaired, and how she healed, but, yes that is possible. Patient needs evaluation and may need possible surgical revision.