Can jinn cause harm to someone who tries to help a girl possessed by them, and what should I do about my feeling of guilt for not being able to help her?

If a girl is afflicted by a Jinn عاشق (lustful Jinn), she must strive to rid herself of it through Ruqyah Shar'iyyah (Islamic exorcism), either by performing Ruqyah on herself or by seeking out righteous individuals to perform Ruqyah for her, while adhering to Islamic guidelines. She should not be deceived by what this Jinn claims about being a Muslim who encourages her to pray, for blocking the means to evil is obligatory. There is no sin upon someone who does not help her, but if it is possible to provide help in permissible matters, then it should be done, due to the virtue of assisting someone in need. Assistance does not necessarily mean that harm will befall you, and one should be diligent in fortifying oneself by reciting the Qur'an and remembering Allah, especially the morning and evening supplications.