Website crashed after adding custom code

I tried to add a custom file viewer to one of my product pages without testing it first. This caused my webpage to crash.

Although I can still access my linked product pages, the content is not visible. I think I accidentally removed the footer while trying to remove the code block.

I initially attempted to link Dropbox to the viewer, but I later realized that Dropbox cannot display the STL file I wanted to use. I'm considering building a new website from scratch, but I'm open to suggestions on how to restore my current one.