Skin allergy experiences

[fairhill]

My mare came in from the field on Monday with raised, sensitive skin on her neck and I wondered if anyone has had experience of anything similar? There are tiny bumps, some swelling of the skin, and she won't let anything touch it so I can't see for sure what is going on. I suspect she's rolled in something, or something has stung her, as she's not had a reaction like this before.

At the moment I'm just lightly rugging her, and keeping an eye on it - is there anything else I could be doing to help her feel better?

Thanks