Heat Rash

Hi,

Recently as weather changes, I get this heat rash on my back, back of thigh, and under the straps of my bra, very itchy, itchier especially during workouts when I sweat.

Any recommendations on how to make it go away? Lotion, brand of clothes that can breathe better, dries fast, or maybe supplment that can help me relieave the itchiness. I have been using the aveeno lotion. It doesn't help much. Thank you