Dreaming of kissing someone on lips usually does not have any meaning and there is nothing to worry about it. Such dreams are product of the intense activity that you had during the day. But if the dream happens without any external influence like movie, television or incidents of the day, then the dream is good.
Dreaming of kissing someone on lips means desire fulfillment especially related to relationships. You might meet the love of your life in future. It is also an indication of sexual encounter in near future.
But as said earlier the dream should happen naturally. Dreaming after seeing movies etc will not have any effect it is just an extension of what happened during the day.