蓝颜变绿
[lán yán biàn lǜ]
This screen name implies the disappointment or betrayal by someone previously thought of as a close friend (blue face) turning into resentment. Green is used here as a symbol of envy or distress in this Chinese phrase, playing on the idiom "blue face becomes green face" (blue often signifies a male friend closer than a brother and not romantic love).