Well, you’ll have to make a quick decision as to the source of the zombie that bit you. Only two sources come to mind. Blood disease, and magic. If it’s magic, you’re already spelled and you’re done. So if you have any hope you’ll have to assume it’s blood transfered.
Consider it like a snake bite. If it’s on your torso or somewhere you can’t put a tourniquet on then you’re done. But if it’s on an expendable limb, use whatever you have handy to cut the blood flow best you can. Then remove the appendage as fast as you can. Help from someone else can be useful here. If you’ve done this fast enough, you may survive the infection.