why does my lip turn purple?

hi my name is tanecia an im 18 years old an i guess im pretty healthy a senior in high school an its like since last year my lip has started to turn purple or blue.. it started last year didnt know what it was an it went away after 3 weeks an now its back! an ive been havin it on the left side of my mouth i would like to know what it is ! plz help!

[Cleveland Clinic]

Lips may turn purple as a sign of low oxygen in the blood.  This typically occurs in kids with asthma or other lung conditions, but may also happen in patients with certain cardiac conditions known as cardiac shunts.  Typically, however, the presentation is not as atypical as yours because the lips, both upper and lower, turn purple simultaneously.  This usually gets worse with exertion.  The fact that only part of your lip turns purple makes it very unlikely for it to be cardiac related.  Do you remember getting hit in that area?   Also, are you having much pain when they turn purple?  Do you take any supplements?  I honestly don't know what this could be.  Consider seeing your doctor and maybe ask for a referral to see a dermatologist.

[Momto3]

Sorry, I can't be of more help.  I'm not sure what would cause your lip to turn purple on occasion.  Have you mentioned it to your family doctor?  

[kinkeagan]

The problem could be identified with my friend who suffered the same last year. Now he has recovered after intense care. He met a doctor who is supposed to be the leading practioner in the country.
He is leading a peaceful life now...

[ireneo]

Wonder if it could be related to Raynauds? Raynauds affects fingers, toes, lips, nose and ears. Not all toes and fingers at a time. Sometimes it's just a fingertip or one toe. It comes and goes with stress or being cold (being cold can mean 60 degree weather or being in the freezer section of the grocery store). Watch and see if you have any color changes (white to blue to red) in any other parts as well.