Urgent!!! Itches everywhere and under the vulva now redness like vein…

Urgent!!! Itches everywhere and under the vulva now redness like veins bursting I've never seen such a thing, possibly due to diapers we're wearing haggies for boys already somewhere for three weeks at the beginning there was no reaction, now with every day it gets worse and worse, what should I do? How to treat? Nothing helps ? on which switch and still everyone says powder I always disliked them, do they actually help?