wp-config.php question

I added these two lines of code to my wp-config.php.

// Enable the WordPress Object Cache:
define(ENABLE_CACHE, true);

Afterward, I read in another thread that it wasn’t advisable to do that, so I removed the two lines of code.

Do I have to do anything to restore my WP blog to how it was before I activated the cache?

Now when I try to sign in I get this:
Warning: Cannot modify header information – headers already sent by (output started at /home/content/f/l/o/fld/html/wh/wordpress/wp-config.php:48) in /home/content/f/l/o/fld/html/wh/wordpress/wp-login.php on line 12