Deleting Possible Malicious File

I ran a scan on my blog (thestylishhousewife.com) and I’ve cleaned up everything I could on my own but there is one I’m not sure about:

The possible malicious file is in this file: wp-includes/class-wp-customize-theme.php. The part that matches a known malicious file is “\x65\x76\x61\x6C\x28”. My question is…can I delete JUST that section or can I delete the whole file without disrupting my current blog? I am sure you will need more info but not sure what to provide? Appreciate any advice!

https://wordpress.org/plugins/wordfence/