I have black purple spots in the tip of my tounge and also on my lower inside of lip. would like to know why ?

Important to check: There is a genetic condition called intestinal polyposis or Peutz Jegher's syndrome. Your age is not mentioned as it often becomes symptomatic in 20s. A colonoscopy is needed for diagnosis, which shows numerous polyps. The pigmented spots on the buccal mucosa are quite characteristic . Ask your PCP for gastroenterology referral. It is important.