(Beverly theme) tried to adjust functions.php now my whole site won't load

Hi guys
I’m really new to WordPress and php. I was trying to get my posts to show up as excerpts, by editing the_content to the_excerpt. I successfully did that but wanted it to say “read more.” So I found a code for that in these forums and it said to post it into my functions.php file so I did. It didnt work so I went back and deleted the coding. But when I tried to save it, it keeps saying something like can’t load page because It could be down or misconfigured. And now if I try to visit my blog or get to the log in page, they are blank and say untitled. I can’t even log in! Help please!