Who is this child biting and head butting? If it is you, then when they child does this walk away and ignore them. Once they learn they get nothing out of this behavior they should stop. If it another child pick up the other child and walk away. Again the one year old will learn that the behavior will gain them nothing and the other child gets attention. If there is a toy or something involved remove it when you walk away.
That can be very frustrating and worrying. I agree that you need to stop this behavior as soon as possible. Toddlers have difficulty expressing themselves and often resort to physical action out of frustration and anger. Tell him "NO!!" sharply and put him in time out for a couple of minutes, explaining to him that he is not to bite or hit with his head. The next time he does it, repeat this. You'll need to repeat this EVERY TIME he does it, and be consistent. Don't grow weary and give up, although it will be tempting. This is just a stage many toddlers go through, so take heart, it will pass, but you need to be firm, loving and consistent. Good luck, you can do this!