How Worried Should I Be?

I was just drying off after a shower and discovered a nasty bruise at the back of one leg.

Like one of those bruises that is purple and red and all sorts of nasty colours and hurts to touch?  Yeah, one of those.

And I have no idea how I got it.

Now just because I don't remember hurting that spot doesn't mean I *didn't* hurt that spot.  But it also doesn't mean I did?

Like is it a pinch?  Did I hit it on something and have forgotten?  Is it some terrible indication of something bad happening at the back of my one leg?  I don't KNOWWWWWWW.

So I put some arnica on it and am trying to just assume it was some injury I immediately forgot about.  Ahem.