Here's one to look out for then, especially if you're on blood thinners.
I had a fall off a ladder (broke fibu.la), off to A&E, heading scan etc., all clear so sent home. 2/3 days later, what's that lump in me neck, ruddy 'ell I feel awful, me 'eads thumpin', I got 'ell of a temperature, I'm having lunatic dreams, and me necks getting bigger. Another 4 days pass, me necks bigger still, and I decide it's time for the doc. Off I go, he takes one look at me, takes me temp, says "Take a seat, I'm calling an ambulance." Off to hospital again, IV antibiotics, more scans than you can shake a stick at. Turns out, during the fall, a tear occurred in soft tissue in top of thorax, causing bleeding and haematoma, which my lymph system considered to be a foreign invasion, so reacted to it and I had blood infection from myself

Whaat!
All because of blood thinners, apparently.
I've knocked 'em on the 'ead after that episode; probably have a stroke next.
So beware; should you have a fall whilst out, and you get any of the above symptoms, get straight round the doc's.