Do you mean the lips on your face? If so, what is wrong with lipstick?
If you mean your lower lips, there is nothing to do to change the color unless it is caused by an infection like lichen schlerosis.
I dont think you can change the pigment of your lips and I see you are from India , Indian women are very beautiful and they use deep red lipstick , I think maybe your hair is black so red lips are great ...
Some tips to get rosy lips.
• Massage your lips with lemon juice .This home remedy will help you a lot in getting rosy lips.
• Apply honey on your lips at bedtime to make them pink and smooth.
• Mix 1 to 2 raspberries with 1 spoon of honey and 1-2 spoons of aloe vera gel .Keep for 5 minutes. Follow with a lip balm or Vaseline petroleum jelly.
• Use one tea spoon of strawberry juice with 2 spoons of petroleum jelly on your lips. Use this mixture as a lip balm.
• Rub rose petals on your lips to lighten their dark colour. Rose petals give your very rosy lips.