我以前皮肤黑现在我皮肤白我以前头发短现在我头发长
可以用以下两种英文翻译:
I used to have dark skin, now my skin is white, I used to have short hair, now my hair is long.
I used to have dark skin, but now my skin has turned white. My hair used to be very short, but now my hair has become longer