Hi there, @TobiasGrill1!
Don here from Shopify. :)
It's very hard for us to diagnose this issue from here without further information, but in the simplest terms, it might be worth just undoing or removing the change you have made to see if that resolves the issue it in and of itself.
If the change you made was to the liquid code (.liquid files) rather than to the CSS (.css, .scss files) then you can simply revert the change by navigating to the relevant file in the Online store > Themes > Actions > Edit code menu.
When you click on the file itself, you will see an option near the top to roll back to earlier versions of this file:
This will allow you to revert to any saved changes made to this liquid file.
CSS changes, on the other hand, are not backed up and you will need to manually undo this.
If you find that undoing these edits does not return your theme to functionality, you may need to download a fresh copy of this theme either from your theme developers (in the case of a third-party, paid theme) or from our theme store in the case of free Shopify themes.
All the best!
Thanks for the reply.
Yes, changing the code in any way seems to be the cause. I think I will keep the changes however and edit the site without the options as I am nearly done.
That said, if you want any further information on this problem I'd be happy to help. Just tell me what you need to know.