I am sorry to note your present state.
The condition that you describe is consistent with urticaria, and very itchy red hives that fade away but reappear within a few hours. Some attacks on the skin are raised and known as angioedema
due to the chemical called histamine
released from mast cells. These cells are present in the lips, tongue, skin, chest, gut etc and therefore wherever histamine gets released, you get the specific organ related symptoms.
Another condition called urticarial vasculitis
definitely needs to be excluded and moreso when there is no response to antihistamines.
80% of people with urticaria do not have any allergies which is the case with you.
Long-acting non-sedating antihistamines like fexofenadine
180mg once daily plus/minus cetirizine
10mg at lunchtime/evening is required for 3 months. Occasionally the treatment may need to be longer if there is a recurrence.
Tests such as CBC, LFTs, renal profile, TSH TPOabs are standard investigations to exclude a secondary cause.
Most people go into remission so do not worry.