Must one re-pray the prayers one performed after masturbating, having erred in purification?

Masturbation is forbidden, and one must repent and seek forgiveness for it.

If the error in the ghusl of janabah (ritual bath after sexual impurity) was in leaving out a part that water did not reach, then it is obligatory to wash the neglected part with a renewed intention, and to repeat the prayers that were performed with that incomplete ghusl. However, if the error was in something other than the intention and ensuring water reached the entire body, then there is no need to repeat the prayers. The correct ghusl is achieved by forming the intention and ensuring water reaches the entire body.