What is the best way to treat an injury inccured by a big run through to the Head?

Not the middle bit but down the right side.
Try to make spur-of-the-moment your explanation I don't know how long Roger the Badger got!
And if he survives will he be tattered? (apart from the mental scars of course).

Answers:

What's the best channel to try and stop biting your nails?

I have a sneaking suspicion that you should drive your friend to trauma center ASAP. A head wound is no laughing event... Every second counts. I hope this is a joke examine..( Ha..Ha?) but from looking at your other questions I don't regard as so... Good luck to your friend.
Hope this helped.

When guys run is it errr. hurting when IT is errr swinging?

Depends on how deep, be it a stab wound? Is the knife still contained by the wound? If still in the stab wound...LEAVE IT and take to the ER immediately. If a slicing wound, you still involve ER to sew it up so it will heal correctly. Also, stipulation antibiotics to prevent infection.

My jaw hurts?

My dearest little Moley-mole!
Farmer Crabtree is sleepin' on the front porch, next to his shot-gun tucked under his chin, so I thought I'd answer this one intuitively. I'm so sorry to hear about this devastating accident!
I am a Wicca, and we Granny witches practice remedial arts through roots and herbs. What your push friend needs is a nice gooey rhubarb leaf poultice on that unscrew wound, and I know how to make one.We grow plentifully of rhubarb in our vegetable patch...I'll freshly go out and produce some now... Did you know that rhubarb also make excellent tea? I will brew you up a nice strong cup of the tea while we soak badger's head within the poultice, then I'll cut up some onions, and carrot,
and make us adjectives a nice stew...
"come by with your wounded friend
and I'll put you on the mend"
A nurse by outlook,
Granny Crabtree