As you describe there may be following possibilities in your case-Eczema
-inflammation of the epidermis resulting in redness, skin edema (swelling), itching and dryness.Cholinergic urticaria
-skin rash brought on by a hypersensitive reaction to body heat following any stimulus to sweat such as exercise , heat from the sun , spicy foods which may cause an increase in body temperature or even stress due to blushing or anger.
As such you need to undergo a clinical examination and undergo Complete Blood Count , Absolute Eosinophil count for further evaluation.
You should drink plenty of water.
You should apply 1 % hydrocortisone cream .
You should apply moisturiser after taking a bath.
If there is associated itching then you can take OTC antihistaminic medication (Cetrizine ).
Do meditation and deep breathing exercises to relieve stress as it can aggravate your symptoms .
Wear cotton clothes and avoid synthetic fibres , perfumes , deodarants , harsh soaps.
Avoid sun exposure , spicy food , alcohol, caffeine , vigorous exercises , hot bath.
I suggest you to consult a dermatologist for further evaluation and management.