Last time I was hit with a baseball bat was over a decade and a half ago. This is what I recall.
A bright flash of purple light was followed by several seconds of darkness, after which I seemed to be laying on my back with people standing over me staring and shouting. This was confusing, as most of those people had been rather far away in the outfield just before, and it didn't seem they would have had time to get there. They seemed quite worried when I asked where they had come from.
The left side of my face stung like the devil, as if the skin was trying to peel off and climb to the back of my head.
So I'd be forced to agree--it does sting to be hit with a baseball bat.
NB: The bat in question was welded by my young sister, who to her credit was actually trying to hit a baseball. When I came to she was weeping uncontrollably. Apparently, she thought she had killed me outright.
I learned a valuable lesson that day--never walk up behind a girl who is swinging a bat. They are stronger than they look.