Smoking, caffeine..: Smoking, high caffeine consumption, constantly biting and licking lips, too much sun exposure, eating hot foods, changes in hormone levels, high levels of iron, and vitamin B 12 deficiency are the most common causes of this uncommon condition. As you already admit to being a smoker, drinking a lot of caffeine, and licking your lips a lot, I would guess these are causing the black spots.
Answered 7/10/2015
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A doctor has provided 1 answer
A doctor has provided 1 answer
A doctor has provided 1 answer
A doctor has provided 1 answer
A doctor has provided 1 answer
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