Parse Error & Unable to Edit???

Hi! I am totally new to WordPress and blogging, and over my head with all of the computer stuff. I thought I was managing quite nicely, until i was trying to add Twitter, and just by opening and pasting (then deleting) the link in the “function.php” under my “theme editor” i now get this error :

Parse error: parse error, unexpected ‘<‘ in /home/content/m/i/s/misssunshine9/html/wp-content/themes/simple-grey-lily/functions.php on line 6

I tried to fix just by reverting to what was originally there, but now I can’t get into any part of my blog. I have no idea where to start to fix this, and I don’t want to worsen the problem.

can anyone tell me what i should do?
Thank you so much!
Laura