帮忙看一下这段英文有没有语法错误 在线等~~~

The story mainly tells us that a shy boy called Danny didn't like his personality and always didn't have much confidence in himself to do things he wanted.So he asked his uncle who was a scientist for help.Uncle gave him a bottle of personality potion.He said it would find out his good personalities inside his heart.Of course,Danny believed it completely,after he tried that,he found himself changed into another person.The potion really worked! several days later,he went to see Uncle.Uncle told Danny the truth that the potion was a trick and he believed himself instead of believing the potion

A several days later,
A去掉

completely应该写成complete吧。修饰it的是adj.