Really, I think we need more information. However, based on what I hear you saying this is what I think. If you have pink blood, you've got some lung, which is great. But, with dark red blood it could be a number of places. Sounds like a shoulder hit with only 6inches of penetration. Sounds to me like you will recover this deer. If you have good blood for 20 yards that at least tells you the shot was not too high. With my experiences a high shot yields very little blood. My experiences with shoulder shots with little penetration is that the blood will be heavy for about 75 to 100yds and then begins to get faint, however, if you penetrated far enough to probably got some vitals. Stick with it and you will probably find this deer. By the way, did you hear the deer crash around alot? Not just running, but thrashing the ground? If so, she probably is not far inside the tree line. Good luck and keep us posted.

Hunt the thickets