Not necessarily. Accusing a woman of being a Prostitute is akin to accusing anyone of being a Pedophile. It is per se defamation. This statement would in fact be a problem for SmashJT, with or without material damages to mercante, but for the niggling detail that she did in fact publicly claim to be a Cam Whore, which is considered by many in "The Public" to be a form of prostitution. In which case the accusation of prostitution is defeated by the absolute defense of the truth.
That is really her only in here, and if the court decides to entertain this case, it will be solely on the legal status of Cam Whores. Are they in fact sex workers, and thus can be called prostitutes in public? While I don't think there is much case law on Cam Shows specifically, there is plenty on strip clubs and pronographic video. Which all firmly holds that yes, cam shows are sex work and thus a form of legal prostitution regulated by the States.
How the State of New York chooses to interpret this, and the Eastern District of New York itself in its precedents will be critical. And this is outside my knowledge. But I would expect her claim that being a cam model is not the same thing as being a Prostitute will face an uphill climb.