What kind of rash is it when you see small bumps and you itch so bad that you could claw your skin off?

Or it could be hives or heat rash ..I would see a Doctor ...do not scratch it

If the rash is localised to a specific area, it could be irritant contact eczema - which means avoid the irritant ie. washing detergents or cleaning agents. You will normally get redness + the small bumps.

If the rash is everywhere on the body could be allergic contact eczema -> avoid the allergy ie. new medication/food allergy/ bad reaction to pollen?

But really it is too hard to diagnose with the information you have given us... in general see your doctor if it gets worse, *avoid scratching it* as this will make it worse, and use a moisturiser to keep the skin moist.