From my perspective deep fakes will lead to a short but massive peak of harassment until everyone is aware of the technology and its capabilities. Once the technology reaches the mainstream and everyone is able to generate such content with ease, people will just stop caring. If these videos are everywhere, it's easy to play it off as a fake. It might even help victims of actual revenge porn. Virtual nudity will become less of a deal, probably even in real life.
From my perspective the bigger issue of deep fakes is news. We already have a huge issue with lies on social media and even TV and newspapers today and once we can no longer trust what we see it will be incredibly hard to build up trust for any sources.
Fake videos of politicians being spread to harm their credibility, fake videos of war crimes to justify an attack. Or vice versa if there's an authentic video of a crime the offenders will just deny the authenticity. But in contrast to Trump's "fake news" claims today, it will be more or less impossible for normal people to fake check anything.