There's a funny rash like that, comes out in sort of feather patterns from the spine kind of thing, back or front iirc. It's some sort of mite that starts off with a single spot.
The simplest cure is, believe it or not, to cover yourself in coal tar shampoo and put on old tshirt and suchlike and sleep on it. Next morning shower and it's dead and gone
No idea where you'll find real coal tar shampoo anymore though
I suppose the Docs will have some ultra safe and tested to the Nth degree expensive pharmaceutical cure nowadays 
Hopefully nothing malignant Rich, and you're on the mend asap.
atb,
Toddy
The simplest cure is, believe it or not, to cover yourself in coal tar shampoo and put on old tshirt and suchlike and sleep on it. Next morning shower and it's dead and gone

No idea where you'll find real coal tar shampoo anymore though


Hopefully nothing malignant Rich, and you're on the mend asap.
atb,
Toddy