I noticed her furiously licking it whilst standing last night - she is a terrible licker of paws normally but only usually when lying down - like a pastime.
I've had a jolly good look this morning and seen the sore. I called the vets, they just said to cool-boil water clean it and try to stop her licking. I trimmed the hair around it to help keep it clean and dry. Vet said to call back Monday if worse.
Any ideas what it could actually be?