I would not be concerned about the head taps.

You can make conscious choices ahead of time to not play contact sports. You cannot always make such choices ahead of time. You can change how you move about life. I suggest slowing down and trying to take on an intentional movement or move on purpose behavior. From this I mean, If you are going to do a movement, move like you have a stiff back or a sore body or such. We tend to move without thinking. Moving intentionally or purposely means we think about each movement.

I learned this because I have a back that does not like quick movements. I also needed to lift heavy objects, 100 to 145 pounds. I needed to climb into tight spaces too and twist and turn. I am also claustrophobic. All of these combine to cause me to move with purpose.

I am not fearful of movement. I know that if I move with purpose, I can do almost any move I need to do.

Learn safe movement skills. Use your OCD to become disciplined to move safely and with purpose.

If you use anxiety to try to prevent bumps, your anxiety will reduce your ability to move with purpose and even reduce your coordination and you will increase your risk of bumps.

A comparison is weight loss. Most who want to lose weight focus on not eating too much. Their anxiety about not eating causes them to want to eat. A successful way to lose weight is to focus on eating healthy food. By simply eating healthy food and not eating unhealthy food, the weight loss is more successful.

So, learning to move with purpose can be just as successful.

Accept that you will occasionally bump your head. That is a part of life you cannot prevent.