Ok all i can suggest is creat a good human skin then amageon a way the person died and show that in the texture then picture in your head and think how the body would have changed the skin would get pale and blueish the damaged areas and cartlage areas would go forst and the rot would spread from there the joints tend to bulge due to rigormortus the eyes would be rotted and shallow the teath would be in terrable condition and lets not forget and dammage and durt that would happen from breaking out of the coffen and slawing its way to the surface can ya tell i am a giant horrer movie buff my friends discribe me as a horrer movie guru lol I hope that this helps you some just rember when the movie ppl do special effects they first research the info then simulate what they have learned by useing the tricks they know and makeing all new tricks anything that will make the viewer think it is real but in real life it loks far mor fake lol good luck and please keep us updated on your progress and dont forget the puss mold and peeling skin lol