A: A child who hits himself is showing you that he's so angry he can't find enough people to blame--he blames himself, too. It is good that you are sensitive to your child's equilibrium, and I would encourage you to look beyond the surface behavior to try to identify what may be causing your son to be so upset lately. Are there changes in his life--in caregivers, in his routine, in the family? Can you identify sources of tension or stress for your son? Is he getting enough rest? Does he feel rushed and pushed? Looking at the big picture might reveal for you some element in your son's situation which you can address so that he is not under so much pressure.
During the episodes when your son is hitting you and himself, I would do what you can to soothe him and to end the episode as quickly and calmly as possible. A child who has fallen apart in this way may need time and attention to pull himself back together. Sometimes the parents quiet, sympathetic presence is best. You might say you'd like him to sit on your lap, if he will not hit you or himself meanwhile. Trying to wrestle with a child who has lost control, or attempting to add "time-out" or explanations--these approaches probably are not too constructive.
These episodes are not unusual. The parent's goal is to live through them and get on with the next thing as calmly as possible.