I Have What I Think To Be A Heat Rash

I have what I think to be a heat rash on my lower abdomen. it first started when I laid in tanning bed a couple times as it done the same last year. I have put just about every over the counter medication on it even a prescribed steroid cream a friend had. the steroid cream all but healed it. but if I don't keep it on there at all times in itches. any suggestions besides going to a dermatologist?