How long does the pain last after a hymenectomy?

Usually not painful. The hypmen is a relatively thin membrane in the vaginal canal and most females don't even know when it being torn. I.E during first relation or tampon use/vaginal exam/pap with speculum etc... Often a simple incisions are aqequate to open the hymen. Some discomfort is common, but if you have excessive pain, consult your doc... Good luck.
Short. Normally les than a week. Would be cautious with resuming sexual relations.