Reading up on Skyaware, it also uses lighttpd as web backend.
Both will try to configure lighttpd for their needs and this will most likely conflict.
Probably you have to choose which one you want to keep.
Or if know lighttpd well enough, configure lighttpd to support both (though unsupported here).
Some tools to play with.
Below tries to reinstall a package from apt cache and is the least intrusive but probably wont fix config file miss configurations:
sudo apt install --reinstall <PACKAGE_NAME>
Below removes a packages but leaves config files untouched:
sudo apt remove <PACKAGE_NAME>
Below purges the package entirely including config files:
sudo apt purge <PACKAGE_NAME>
If you want to keep/restore Pi-hole, you would have to purge the lighttpd package including reverse dependencies and config file(s) that most likely were modified/added by Skyaware.
Running below and selecting repair should fix the rest:
pihole -r
If that dont work, post a debug token here for the mods/devs to have a look.