Malware warning from google

Hi. I just learned today that my site is flagged by Google as hosting dangerous content. It seems something injected a javascript line into 3 html files on my website, including the index file, with a link to . js. This looks to have been done in late September. Did anyone else have this happen to them? What caused this? It would seem this would have to have been done server side… Is there something more I should do about this than just replace the offending html files?

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