Hello Friend, Good that you are seeking a help. Your problem needs further evaluation to suggest a solution. It may be  loss of concentration due to too much thinking about some past incidents or unhappy memories and your behavior is something similar to people doing nails bitting while thinking. I know it's an awkward habit, but definitely correctable. The solution is to first figure out and analyze the kind of the thought you are having at those times. Based on that you can control your behavior. You need to meet a psychiatrist locally or can reach us online.

It's unlikely to be an OCD. Go for counseling it might help you figure out the whys of the situation and how to get rid of the habit.