What are the consequences with Allah of a young man exposing a girl after she has repented, and what should the girl do about it?

Your remorse and repentance for the forbidden relationship are commendable. We advise you to be diligent in maintaining righteousness and avoiding everything that leads to ruin. If this man threatens you, falsely accuses you, spreads pictures, and insults your family, he has committed a great wrong. The Shari'a calls for concealment, especially if the sinner has repented. We fear that he may be among those about whom Allah said: "Indeed, those who like that immorality should be spread among those who have believed will have a painful punishment in this world and the Hereafter." You must be careful not to respond to his demands; rather, be firm and threaten him with reporting the matter to the responsible authorities. Turn to Allah to protect you from his evil, and among the suitable supplications is: "O Allah, we place You in their throats, and we seek refuge in You from their evils." It is audacious and insolent for him to interfere in the affairs of the Lord of the worlds and claim that what he is doing is Allah's justice upon you, for he does not know the unseen. And you must be patient and supplicate, for all this tribulation will not be in vain. Through patience come blessings, elevation of ranks, and expiation of sins. Do what is within your power, and stop thinking about what is within his.