There are a few porn stars who have tried their hand at writing novels, but it's not a very common thing. Maybe some do it to showcase a different side of their creativity.
Some porn stars might attend certain adult entertainment conventions, but not typically Comic Cons as we commonly know them. Comic Cons are mainly focused on mainstream comics, movies, and related pop culture.
Some porn stars regret it because of the stigma and judgment they face in society. It makes it hard for them to have normal lives and relationships outside the industry.