Google - small itchy bumps?

Ok, so firstly I don't know what this is, but you shouldn't be putting any chemicals on your feet until you know what you're dealing with.
It sounds like a heat rash or prickly heat (I don't know where you're located) so maybe forgo wearing trainers for a couple of days and let the air get to your feet. Is the rash on both feet? Soak them in salty water but honestly, any other chemicals on broken skin can make matters so much worse. To help with the itching you could try getting calamine lotion from the local chemist (an old fashioned lotion used to help with the itching in chicken pox) or even taking an anti histamine (again get from the chemist). Don't scratch the tops off the bumps, you'll only make it worse.
Wear natural materials on your skin, so cotton socks and footwear that doesn't make you sweat so badly.
Good luck.

need to be real sure that once you see the dr that he has some good ideas might gotten your self there alot going round you have to be careful