touch something up
phrasal verb with touch verb uk/tʌtʃ/ us/tʌtʃ/
（稍加）修饰，润色
to improve something by making small changes or additions
She touched up her lipstick and brushed her hair. 她补了补唇膏，梳了梳头发。
We thought the photo had probably been touched up, because he looked so much younger in it. 我们觉得照片很可能修饰过，因为他在照片中看起来要年轻得多。