Oral Melanotic Macules?

I am 17 and I had severly dry/chapped lips a few years ago, they have gotten better but over the years,I have noticed freckle-like spots on my lips. The colour ranges from hardly-noticible light brown to dark brown. They have been compared to smudges of dirt and chocolate. They don't hurt, but they attract unwanted attention; peoples' eyes seem to be automatically drawn to my lips, making me extremely self-conscious. I do not smoke, but I do drink green tea occasionally. I have about 1.5 litres of water a day and I am a flexitarian. There are some local dermatologists, but it is almost next to impossible to book an appointment with them.  

My questions for you guys are:

1) What the heck are these things?
2) What is the cause?
3) Is it possible to remove these spots? How?

Thanks in advance <3


- Seriously Annoyed Girl