a. This appears to be a shot man.
b. This appear to be a man shot.
c. This appears to be a man, shot.
If 'a' is said on its own then, although it may be correct, it is not usual - "....a man who has been shot." is better. If in a scene where a lot of injured lie around then someone may just be saying: a shot man, a knifed man, a strangled man, and so on.
'b' is wrong - appears. Then see below.
'c' is right. But equally "...man, who appears to be shot/ appears to have been shot".