Skin concerns

I really don't know what to do.

When your body temperature rises (such as when you're hot, after a shower, during exercise, or suddenly feeling flushed), red spots appear on the skin, accompanied by a burning sensation and itching, and they look unpleasant.

The hospital gives antihistamines for cholinergic dermatitis, but they don't really help and aren't a cure; they only alleviate symptoms. Is real treatment difficult?

It seems to be 3 or 4 years old. Please tell me the treatment options.