Any home remedies for prickly heat rash?

I don't have any skin conditions such as psoriasis or excema, and I don't have any skin allergies. It's definitely heat rash of some sort. I just get patches of itchy rashes during the summer when it's hot and humid. I have been China for for years and TCM hasn't helped much. Right now the best relief I can get is from taking a hot shower (to open the pores), covering my body with shampoo or other products containing menthol, waiting about five to ten minutes until my whole body tingles. After that I rinse with hot water again (to clean the products chemicals out of my pores), then a cold water rinse to close the pores and cool off. This is usually only temporary relief. I do sweat a lot (more than most people), so I take about three cold showers a day too cool off and clean out the pores. I do refrain from scratching (as I know it makes it worse) during waking hours, but during my sleep, I have involuntary scratching. I am really into alternative health and home remedies. Thanks