Anger, pain, excitement and many other emotions bring out a sudden reaction from us in the way we least expect. There are 3 aspects to what you have expressed. Firstly You felt that your intensity of anger under situations is more than the situation commands. This usually is the case when there already is a pent up anger within you about the person you are reacting to, about similar situations, or even generally which is getting expressed whenever situations or people do not behave in the way you expect them to. Secondly you feel that your behaviour also is exaggerated compared to the trigger. You also might have noticed that every time you are angry, you tend to behave more or less in a similar way which is your reaction pattern for anger. You need to understand this pattern thoroughly and see when you can intervene and console yourself to break the pattern. Third aspect is your feeling helpless and harming yourself to relieve the anger. You harm yourself because you are the easiest target under situation. Anger as you have observed is a high energy state. It will be forcing you to act in one way or the other to get back to your usual state of mind. Just think about different ways to express it like involving in a physical activity or a hobby, immediately when you are angry. Relieve the tension and think about your take on situation/write it and communicate it calmly to the other person. So you need to work on the pent up anger, reaction pattern and alternate response mechanism. Remember that anger is just a friend which helps to know yourself better and to express it appropriately to others in the way they understand. You can also consult a psychologist who can help you further in the process. Take Care.