Thanks for the query.
It is unlikely for the vagina to develop a sudden swelling that has got noticed after a nap.
It could mean an acute reaction, for example, an insect bite, which can develop into a sudden swelling. Any food or cosmetic allergy applied over the area, new soaps or lotions can also cause a swelling.
Kindly consider consulting a gynecologist for an examination and specific medications for the swelling.
Hope this helped.
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