Lips

The other day I woke up and noticed that my mouth/lips felt chap, and I went about my day applying carmex as usual, but the following day ii noticed that they felt tight, and had a burning sensation and looked a little swollen. Two days later I had a black coloration to my lips, and today they are even darker, what could cause that and what should I do. I was told to apply vaseline, not carmex. I've never had oral sex, so I know thats not the issue, and I have been using the same lipliner for awhile. If I put anything on my lips but vaseline, like carmex, lip moisturizer, lip balm, it burns, and this has never happened before. Will my lips retain their original color?

I am a black woman with light toned lips, that now look like I am wearing dark lip liner or gloss.