W managed to rememeber that she had an "After Bite " stick, one of those with the 3.5 ammonia in it. So I put that on it a coupla times. I also have some antibiotic cream which I had been putting on it.
After a night's sleep it is a lot better and the redness has reduced. Just a tiny little pus-filled head which I am keeping clean and treating.
So much less painful I can walk on it much better and even put my wellies on again!
I kept them indoors last night and inspected then very carefully before putting em on!
But yes, as you say according to t'internet they can get very nasty! And I am 99% sure that it was a spider. Thanks for the concern.
Did he have to have ops to cut away necrotised flesh etc?