Could use a little touch up.

可以重新润色一遍。

Shall I touch up your hair today?

要不要今天给您把头发修一修？

Shall l touch up your hair today?

要不要我今天给您把头发修一修？

I must touch up the chipped paint on my car.

我必须修补一下我汽车上的油漆脱落处。

He asked the teacher to touch up his picture.

他请老师把他的画修改一下。