My own horse came in with the most horrendous rash which consisted of large raised lumps all over his body - the photos (1&2) really do not do it justice as he was absolutely covered along both sides of his body and the lumps were huge.
We had just crossed from winter stasis, where the body naturally slows down all of its processes which results in toxins building up, into Spring where everything goes into hyperdrive. Sometimes the various bodily processes can't always work quick enough to expel all of those toxins that have been increasing over winter. I suspected that this was the route cause of my horses crazy rash and so I very quickly provided him with a herbal self selection session that included (but was not limited to) various herbs and oils that assist with general detox. Jerry largely selected herbs that provide support for the liver - he only chose about 3 products from an offering of about 15.
The 2nd & 3rd picture was taken within 20 minutes where the rash had virtually disappeared and the 4th & 5th picture was the following morning where it was no longer visable as a lumpy rash, just a couple aras where skin remained a little uneven. Jerry knew exactly what he needed to sort himself out - I just had to provide access.
(Pics can be seen in attached file)