I know a lot of people will disagree with me, but the facts of the head butt have to be looked at on their own.
There's no doubting the provocation, which should have been punished with a yellow card, and some posters on here have said how hard it would be not to react the way he did. Posssibly for a lot of people, but it has to be remembered that he is a professional, and has to accept the fact that some abuse will be directed at him, but that's still no excuse for vioent conduct. This was also an assault, and just because it happened during a football match, again, is no excuse.
Had he yelled back, then both would have had a possible yellow card or a blasting from the ref.
I know first hand about being provoked, and over the years have had plenty of players yelling in my face, and I took appropriate action. If a ref was to head butt a player who had provoked him, do you think as many people who are on here defending Aaron Muirhead would defend a ref.
Don't get me wrong, I'm gutted Thistle lost, but the reaction was the wrong way to go about things.