Hi Sam, Have you tried apple cider vinegar or ACV, use or the prickly heat after washing.
Or Prickly Heat Powder form the British Dispensary Thailand, in either classic or antibiotic, these two are courtesy of earthclinic.
Good Luck
The best solution to allergic reactions to perfume is not to use it.
If you do want to wear some perfume, put in on your clothes rather than directly on to your skin.
Prickly heat can be cooled with calomine lotion calomine cream. Your pharmacist should help with these.
You could also try antihistamine medications.
But the best thing is to avoid the irritant or cover your skin.
Best wishes
The most important thing is to not wear perfume in the first place. Trust me, as long as you don't smell bad, no one cares. And some of us much prefer it when people forgo the perfume (it burns my nose).
I would not put neosporin on heat rash if it's not infected. You want the area to stay nice and dry, not all gooey, and there's no need for the antibiotics if you don't have open sores. I've never heard of baking soda being any good. Since you're sensitive to perfumes, use some plain old cornstarch on it to keep it dry and from chafing. If it's itchy, a little hydrocortisone might help. Keeping the area clean by taking a wet wash cloth to it in between showers or after sweating should help prevent it. I also put unscented gel deodorant on my inner thighs sometimes to keep from sweating and chafing and getting a rash.