Not a boil or blister. Spider bite? Scar?

[qwerty123450]

Hello.
I have recently noticed a strange blemish on my right side about 5 inches below my armpit, just on the outskirts of my back. The best way I can describe it, it looks like a reverse stretch mark; instead of the blemish being a bit sunken like a streach mark, it is a bit puffy. It is a noticeable lump, oval in shape with another oval-ish blemish in the middle of the blemish, about an inch long.

It does not hurt, and is not hot. I have tried both hydrogen peroxide and alcohol, there is not pain or bubbling. It is only not red because I have been poking it for a while. It dies not feel hard, there does not feel to be a head or puss under it.

The strangest thing is that when I bend my side inward, the blemish looks as if it could close right up; It looks as if the skin has been split open.

I have included an image of it. I'm pretty sure I would have remembered something happening to leave such a scar, if it is a scar. Any ideas if it is in fact a spider bite? Or a blemish? Or just an imperfection in the skin I have never noticed?

http://i51.tinypic.com/2wgdwnt.jpg
http://i54.tinypic.com/214yt7l.jpg

[qwerty123450]

One more question. The only thing I think that could have caused this was a fall down stairs about two months ago. Would it be possible for a scar to form so long after an injury?

[qwerty123450]

I'd also like to add that, not only does it not hurt, I don't seem to feel anything at all at that area. When I touch it, I feel nothing at all, not even myself putting pressure on that area.