My daughter's skin around her lips are blue (looks like a bruise) but i was with her all day and only noticed it now. it isn't painful. but i'm a little worried?

Details matter: It depends on what the "bruising" is like, how old the child is, what sort of activities she does, etc... If there are no signs of trauma in a happy, school-aged child who shows up with purplish dots or splotches under the skin around the outside of her lips, the best guess is she put a cup over her mouth and sucked until the vacuum pulled blood spots into her skin... a common "fun" thing kids do.