Lightened Lips HELP!!!!!!!!?

Okay i'm black and about 3 weeks ago i used the new Ambi Skin Care Essentials Gentle Cleanser and i left it on my face overnight and the next day i noticed that it had lightened the thin line on my above upper lip below the philtrum now its like 2 shades brighter than my lips, please is there any way i can get it back to its normal color. I've been smearing a small amount of petroleum jelly on that line only because i heard it darken lips if used over a long period. but seriously i don't wanna lighten my whole lips i just want to bring that line back to its original shade. PLEASE CAN SOMEONE HELP ME!!!! :(