I feel gross

I've had sex with my boyfriend and I am now just realizing that my lips down there are really dark. I asked him if they've been that way and he said yes. It makes me uncomfortable and I feel really gross about it because it's not even brown. It's black and I'm a relatively light brown girl. I wash it and really take care of my vagina and all that comes with it. Is there anything I can actually do to change that or am I stuck with it? I feel really uncomfortable now that I saw it. My boyfriend tried to make me feel better about it but I feel bad for me, not him. So can you guys please help me. :(