Hi, I've seen Rain rot/scald before and I don't believe that is whats wrong with Beamer. I'm not going to say I'm 100% certain, but I do think it is wisest to call your vet. :)
Rain rot can appear as large crust-like scabs, or small 1/4 inch matted tufts of hair. There is usually dozens of tiny scabs that have embedded hair and can be easily scraped off. Underneath the scabs, the skin is usually (but not always) pink with puss when the scabs are first removed, then it becomes gray and dry as it heals. It is usually hard to differentiate rain rot from other similar skin conditions, so if you are unsure
, call your vet.
In the early stages, you will be able to feel small lumps on the horses' skin or hair by running your hand over your horse's coat.
Rain rot effects the back, rump, fetlock area and canon bone area. It can on occasions effect tips of ears, around the eyes and muzzle.
You need to do what you think is best. Let us know how things go.