What's another choice? Pick yourself up, note your mistake, and try again. The new match begins right now. Really: right now.
It does not mean being quiet about injustice.
It means quietly doing what is necessary, dropping it off, and responding to the next moment without a trace.
Off you go! When you keep trying, stumbling, and faithfully trying again for 5, 10, 20 years - a widening perspective on courage and diligence appears. You can't practice forgiving yourself for that long without also forgiving the world.
Great diligence is the willingness to shuck everything and start again from zero. That is the paramita of dilgence or unceasing effort (virya). It is one aspect of what you truly are.