HELP! So, I followed an online tutorial on how to export my images from Lightroom (it was WRONG) and now my images say "not recommended for print" when the size is greater than 4x6 because of low image quality. Problem is I don't have any of the original files, only the edited files (mistake, I know). Any way to fix these edited files so they will have a better print quality?
If the images are a certain size in pixels, you could blow them up to a larger size in pixels, but the quality will decrease. So I think to answer your question, there is no way to fix these files.
What you need to do is to keep the original files in Lightroom from now on, so if you make a mistake exporting, you just export again with the mistake fixed. You also need to make regular and automated backups of your original files and also a backup of your catalog file, stored on a different disk, so that no matter what mistake is made and no matter what hardware malfunction might happen, you still have a copy.