How To Get Rid Of Pigmentation On Lip?

I have dark corners on my lower lip. Overall, my lip color is pink but corner of my lips are dark. I have tried rubbing lemon and i massage my lips with olive/almond oil before going to bed. I also tried exfoliation method with sugar and lemon. but the corners are still dark. I have a little bit dark color on my upper lips too. Help me please with any medicated cream and home remedy. I am getting married in next month. Stay Blessed