(Picture from CK Hon)
Welcome back! So you went ahead for the fight. It takes courage and character to be able to apologize to the other party. You are on the right track.
The Buddhist concept of kamma is a very complex subject. You must also know that kamma is not the only influencing factor that affect our lives. There are other factors, namely, the organic or genes; the physical like seasons; the mind or consciousness; and the natural order of phenomena like natural disasters. Kamma is the overwhelming factor that affects and influences our lives. However, we must understand what is this kamma. Kamma means action with intention; or volition. Things you do on purpose. In your case, you have done something intentionally, and this will cause a reaction or result. You can say kamma works in "mysterious" ways. We do not know when the reaction(s) will materialize. Also there are so many actions that we have performed, both good and bad; some good actions may overshadow the bad, and vise versa. So the best bet is to strive to perform good actions, and to avoid bad ones. It is common sense that actions performed cannot be retracted. This gives us more reason to be very careful with our actions.
Smile from justinchoo :-)