All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is not permissible to swear by supplicating against oneself for evil or for entering Hell because the Messenger of Allah said: “Do not invoke curses on yourself or on your children or on your possessions lest you should happen to do it at a moment when the supplications are accepted, and your prayer might be granted.” [Muslim]
It is necessary to repent to Allah for that. If one swears that he is going to be in Hell, then he should ask Allah for forgiveness, regret what he did, and resolve not to do that again.
What was mentioned does not mean that a Muslim will be deprived of entering Paradise or that his destiny will be in Hell.
Allah knows best.