No. 花言巧语 It's a derogatory word meaning some beautiful things people say to gloss over the truth in order to reach their goals. 甜言蜜语 It's a neutral word just meaning beutiful or sweet talks.

Steven Halim, I agree with mouzhong's answer.

No. 花言巧语 glib, implies deceit. 甜言蜜语 = sweetalk

No, they are not the same "花言巧语" means deceiving words. you use this kind of speech to trick someone into doing something beneficial for yourself. "甜言蜜语“ means sweet words as you say. this kind of speech is used for people you love, usually your boy/girl friend or your wife/husband

*have lol.