Hogs have a vary large reservoir of blood in their neck. It enables them to go for ever bleeding. As for the spots, hogs that are feral can be of any color as they are escaped domestics.There is no telling where you hit it. Them dudes are tough. I have hit them in the neck and between the shoulder blades and them bleeding like crazy and still not find them. Just try to get another shot in it if you can and hope for the best.