I would not worry about this. After 10 days your grafts should be secure. It never hurts to follow up with your doctor that performed the procedure either. Better safe than sorry is always a good policy.
Casually bumping your scalp should not cause harm to the transplanted grafts. If you are concerned you should follow up with your doctor.
By this time the grafts are generally secure and if you did not see bleeding, then I doubt that you did any damage to the grafts.