少年年少不懂事把姑娘用旧
[shăo nián nián shăo bù dŏng shì bă gū niáng yòng jiù]
'Young lad who does not know how to value the girl' - This nickname expresses regret and apology for someone (likely male) who mistreated or took advantage of another individual (likely female) due to youthfulness or immaturity.