I don't think you can just get one laser treatment and have all of the hair permanently removed. You need to do multiple sessions to catch all of the hair and kill the cells from the root. It doesn't matter if the place is good, it's almost impossible to get rid of hair in one session. From what I've heard, if they do it right it should not hurt because they apply a cream of some sort. As for the redness, it varies depending on how sensitive your skin is. But if there is any redness it should disappear within a few hours.