Correction

Opinion

More natural/my way

Messy Hair

“My sister was so annoyed. She kept saying that my hair is messy and dry, and that I should put some cream on/in it,” my mom said.

“Your hair does look messy. She's only saying that/telling you that because she cares about you. She wants you to look clean,” I said.

“Your hair does look messy," I agreed. "But she's only saying that because she cares about you. She wants you to look clean."

Mom kept silent, then she put some cream on her hair. Mom finally understood her sister’s words.
Everyone embraces sweet words; however, sweet words are like a colorful mushroom. They often have poison as well. Honest words are like knives. They cut your heart. You feel angry and saddened by honest words; however, they can make you change to a better person.

Sweet or honest words? It is your choice.

I'm not 100% sure what hair cream is or what you're talking about so I'm not sure if you can only put hair cream "on" your hair or "in" it too.

I understand what you're trying to say by "She cares you for saying that." but it is not quite correct or natural. There are some different ways to express this meaning.

In gray, is a different way I might use quoting.

You need "a" before "colorful mushroom".

You might want to add "as well". Your sentence is okay but adding "as well" emphasizes seeming sweet but being poisonous. In the same way, the mushroom seems colorful and inviting but is also poisonous. It shows more contrast "It's sweet (so you expect it to be very nice) but ALSO it has poison (which is very different than you would have thought)." 

I think you meant "sad" instead of "said". Since you have "by" following "sad", it should be "saddened". "Angry" could remain angry or change to "angered", with a slight change in nuances. I would keep "angry". 

Capatilize the "i" in "It".

Messy Hair

“My sister was Your aunt is so annoying! She kept saying that my hair is messy and dry; , and that it I should put some hair gel on it.  cream,”  沒錯, 太古老了, 現用 "mousse" 或 "hair gel"my mom complained said.

“Your hair does looks messy. She only tells you because she cares you for saying that. She wants you to look smart. clean,” [婉词] I replied said. Mom kept was silent. then Afterwards, quietly she put some cream some on her hair. Mom finally understood her sister’s words.

Everyone embraces sweet is conducive to honeyed words. However, sweet words they are like colorful mushrooms. They often Pretty looking but often laced with have poison. Honest words are like knives. They cut your heart. You feel angry and said by when honest words are spoken; [忠言逆耳 :) ]However, they can make you can't catch flies with vinegar!  change to a better person.

Sweet or honest Honeyed words or the honest truth? it is Your choice.

两样我都不要! 做人要学長孫皇后, 以恭賀唐太宗的方法 来直諫皇帝对魏徵不滿之处 :)

Messy Hair

“My sister was so annoyed. She kept saying that my hair is messy and dry, and it should put some cream,” my mom said.
“Your hair does look messy. She cares you for saying that. She wants you to look clean,” I said. Mom kept silent, then she put some cream on her hair. Mom finally understood her sister’s words.
Everyone embraces sweet words; however, sweet words are like colorful mushroom. They often have poison. Honest words are like knives. They cut your heart. You feel angry and said by honest words; however, they can make you change to a better person.
Sweet or honest words? it is your choice.

Messy Hair

“My sister was so annoyed. She kept saying that my hair is messy and dry, and it should put some cream,” my mom said.

* "My sister was so annoyed, complaining her mess and dry hair all day! Why don't she go to buy ... "