Installed WP in subfolder before adding on as a domain…

HI,
I am hoping someone can let me know my options to get out of this little mess.

I have a main domain under which I typically install add-on domains. In this instance, however, I created the folder and installed wordpress and THEN added on the domain. Now my blog will not work properly. If I try to go directly to https://www.myblog.com/somepage/ i get a 500 error.

I am only using wp in this case so far for pages and not posts, so the content that I have in there could be easily moved by hand.

What are my options at this point?

Thanks!