Lips pigmentation please help

I have lips pigmentation and I want to get rid of it , I have asked so much to chatgpt about this , suggested - eating foods like carrots , beet many more etc , which I do eat as he told me but it doesn't seems to be Helping I was searching for a product and came across melalumin but there are mixed reviews about it , please suggested something which will actually help any product or anything in budget Cause of pigmentation - Sun exposure & toothpaste