I think maybe you might be misunderstanding how github works?
The pr is still there, just closed, and can be re-opened.
It looks like mugling was going through merging things, and was reviewing your pull and found a bunch of unrelated file changes in data/json/recipes/recipe_medsandchemicals.json to your mod, where you added/removed a slew of flags to a bunch of recipes that seem unrelated to the mod.
These changes would have caused a regression in the codebase so it would have broke stuff to merge it, but not merging it was blocking a bunch of other PRs. Mugling closed it pending changes.
If you change the files on your local repository to not include the random unrelated-to-lamia mutation changes you made to that file, I’m sure you can ask mugling to re-open it and consider it.
It’s also possible (though I didn’t check) that you could be working off an older version of recipe_medsandchemicals.json, and that you didn’t actually change them, per-say, as someone else changed it and you have an older version before the change and github is interpreting it as a change. To fix it you can make a backup of your changes, rebase your git branch, and then specifically copy in your changes to the files.
Also, is it possible that these changes could be done in the form of a mod, rather than a modification to the base files? That might make this 100x easier to add into the main branch.