Prickly heat treatment?

[MortyFide]

Bizarrely, I seem to have developed prickly heat on my upper arms. Yesterday I put some moisturiser on (Aveeno) before going for a short walk, mostly in shade, but by yesterday evening I had patches on my upper arms that were burning like sunburn.

By this morning it was a raised, bumpy rash and its burning and prickling like mad - I had it once before in Cyprus, I wanted to tear my skin off!

I already take fexofenadine daily for hayfever, so that's not helping much - what's something good I could put on it? All I have in the house is e45 moisturiser, bepanthen, savlon, germolene or nivea aftersun.

Might get to a pharmacy tomorrow? Any home remedies?!

Are you sure it's prickly heat?

I randomly became allergic to the sun a few years ago. The only thing I can use that works in preventing that awful itchy rash, is Piz Buin anti allergy sun lotion.

But if I forget to put it on and I do get the rash, the only thing that calms the itching is Piriteez and Sudocrem.

Well, I just assumed it was, although it doesn't look much like the prickly heat in Google images, I admit!

It's like twin patches of sunburn, one on the same place in each arm,. The patches have raggedy, spotty edges, although it's mainly just red and raised/welty. It burns and is prickly/itchy.

I do have sudocrem!