Theme loop.php mess up

Anyone who has the idea of theme editing should please help me.
1)I wanted to display only excerpts in my homepage instead of the full post
2)I changed _content to _excerpt in loop.php of my theme editor.
3)After i saw that my desired goal was not achieved,i decide to change back to it’s original form.
4)Only to see “?????????? ? ???. ?????” at the end of my posts(You can check it out HERE,just scroll down to the end of the post,beside “Read more” to see what i am talking about).
5)Please can someone give me an honest solution to this problem?