What is the prescribed Islamic action for someone who was unjustly beaten and was able to retaliate?

Allah has permitted the wronged to retaliate in kind, yet He has preferred forgiveness and reconciliation, and described the righteous as "those who suppress their anger and pardon people." The Prophet, peace and blessings be upon him, said: "Allah increases a servant in nothing but honor by his forgiveness." Taking retribution (qisas) must be done in the presence of the ruler or the Sharia (definition) judge, because it is a matter that requires careful deliberation and in which injustice is feared.