The goat can symbolize a lot to a man depending on who you ask. For example, the goat has symbolized male potency and virility. The Greek, on the other hand, believed that the goat symbolized the wild part of a man and some prowess.
One should not forget that the goat also symbolized evil, especially when seen through a Christian perspective.
Many Christians believe that the goat symbol is used in witchery and other unmentionable practices, meaning that you might scare a nun or priest with your goat skull tattoo.
The dead goat skull could definitely be associated with the dark arts, which is pretty bad ass already, but it could mean a lot more. For one, it could symbolize the typical ancient man, who was supposed to be strong and a bit male-chauvinistic.
It could also represent the death of that man, as there is a new man in you; that man remembers his power but reserves it because this is a new era. The dead goat could say something about a man that is a little more cynical.
Perhaps, to you it symbolizes that life’s vitality is winding down because people are simply not taking care of mother earth as they should.