speaking about regret, do you regret the truthful that your confess to other is unacceptable by them??
There would be no regret to reveal the truth, as long as that truth is NECESSARY to be spoken, with no intention to hurt anyone. Should it be painful to someone, she/he would better face it, therefore she/he could manage some action to deal with it. White lie seems to be right at the first place, but it can draw back somebody to the worse situation.