Large hematoma from a subcutaneous injection. A blood vessel was apparently nicked during the injection causing local hemorrhage and a mass of clotted blood (vigorous rubbing of the site following the injection may have caused excessive bleeding). 

Hematomas usually resolve on their own over a period of weeks or even months. This one was over six months old and had apparently walled itself and possibily even continued to have at least seep into the area from time to time. 

It had no "head" until I bowed to pressure from friends that were certain it was an abscess and I should apirate it. The attempt (I got nothing but a few drops of sera) simulated that area and it quickly become inflammed, irritated, increased in size, and began forming a possible "head" area, of course she messed with it until it opened up.  :-(

There was never any discharge from the open area and it only bled when the doe got to it. There was no sign of infection or purulent discharges. Nor could I extract anything out of it via pressure.