heat lumps are often referred to as urticaria by our medical freinds ( though this is a little woolly). The little blisters thing sounds like eczema/ contact dermatitis. Normally a steroid cream such as daktacort will calm it. however you need to address the problem....have you recently changed diet? or washing powders? both of these can lead to reactions.
IF it becomes certain that this is not an allergy, then scabies is a good second guess, particularly if you have or work near small children (natures perfect plague rat).
You do need to see a dermatologist. insist, in fact.