Is it permissible to lie after confessing to someone about committing an indecency, and then retracting this confession by saying that it did not happen?

Whoever falls into sin must conceal himself. If he informs others of his sin, and then wishes to retract his statement, he may do so, just as in the initial situation. So, if someone confesses to an indecency before a judge, he is permitted to retract his confession; indeed, it is even recommended for him to do so.