Should I inform people that I lied to them about a person's death to avoid openly committing a sin, or should I conceal myself, and how can I stop this lie that neither harms nor benefits, and will I be questioned about it on the Day of Judgment?

Lying is forbidden by Islamic law, by the consensus of the Ummah. Repentance from it is obligatory by desisting, regretting, and resolving not to return to it. It is not obligatory to inform those who were lied to, unless the lie caused harm. One must refute oneself in front of the listeners when the lie involves bearing false witness or slandering a Muslim. Repentance from slander is threefold: resolving to abandon it, seeking forgiveness from the slandered person if possible, otherwise supplicating and seeking forgiveness for them, and refuting oneself in front of the listeners. If the lie did not cause harm to those who were lied to, then they have no claim against you in the Afterlife.