Has anyone seen anything like this?

Day 2 of this thing on my mare - it seems to have gone down in size a bit from yesterday! Cold hosing twice a day, silver honey & swat fly rub around it.

I got some better pictures today - it’s still pretty firm but no heat and I can mess with it however I want and she doesn’t seem bothered at all! Not lame & eating/drinking fantastically.

Does it look like she rubbed it on something, a breastcollar clip rubbed to much or maybe a sarcoid?

Just trying to learn! Has anyone ever seen anything like this?

Vet was called and they didn’t seem worried! Said to cold hose and keep flys off it as much as possible.