Answered by Shaykh Faraz Rabbani
Does a woman have to peform ghusl after a pap smear/pelvic exam?
Answer:

Walaikum assalam wa rahmatullah,
No, ghusl is not required from it. Rather, ghusl is only required after: intercourse; ejaculation; menstruation; and post-natal bleeding. [ Shurunbulali, Maraqi al-Falah ]
And Allah alone gives success.
Faraz Rabbani