Want To Get Back The PINKISH look of your lips again, Dont worry!!
Just follow these tips and notice the change:

Dark lips may be due to an unhealthy diet and unsuitable lipsticks. So eat healthy and stop using lipsticks which are bought at very less price.
Sometimes the lips may darken due to a food allergy or a bacterial allergy. So if these tips dont work for 2-3 weeks then take a food allergy test.

Because the lips are soft, we cannot exfoliate them as often we exfoliate other parts. .. but not exfoliating them usually results in darkning of lips.
#While brushing your teeth every morning try out to brush on your lips to ‘peel off’ the dead cells and boost the growth of new cells.
#The other way to exfoliate your lips is to apply glycerin to the lips first then put on a bit of lime juice and allow it to get soaked up.Then tighten the lips by opening the mouth and use your finger by gently rubbing along the length of the lips, like brushing the teeth.You will see that the skin is peeling off.Then you may apply vaseline to soften lips.

#Drink at least 8 glasses of water each day. It improves your complexion while bringing back the original colour of your lips.

Use a paste of Almond with Malai with a few drops of lemon juice added and massage this into your lips twice a day.

Apply a little cream (from milk) before turning in for the night everyday, your lips will turn pink and healthy in a few days. Milk cream is a layer of cream that forms on milk after heating it on low heat for 10-15 minutes.

To reduce darkening of the lips, it is also good to apply cleared up butter to the lips and leave it on all-night.

Mix well equal amounts of almond oil, honey and glycerin with rose water, shake and apply.Wash it off after 10 minutes. Do it for some days and notice the change.

While going out in the sun apply a moisturising lipstick with sun-block. and remember just because lips don’t tan doesn’t mean the sun rays don’t harm them.
#Remember to wear a lip balm with SPF 15 or higher to protect your lips.

Put on some vaseline petroleum jelly , then rub over your lips with wet toothbrush, and instantly they will get a bright red colour. The dead layer of your lips will stick to the toothbrush so reapply vaseline for moisturizing lips. Repeat this for days and notice the dramatic difference.

For dark lips try this out…..Smash coriander leaves and apply this on lips overnight…and see the difference

As a home remedy use fresh cream with cooked beetroot paste to give your lips a nice healthy tone.

Apply lip balm before turning in for the night. If dont have a lip balm or Vaseline, Eye cream is a great subsitute

Dont worry about black lips, try to apply toothpaste with neem in it before you go to bed. In some  days, you will see the better results.