A dry skin needs a moisturiser. Plus, if you have a severe rash (which you say is prickly heat) you will need active treatment, possibly with a mild steroid cream( Don't worry... it's safe ONLY IF USED UNDER the GUIDANCE OF A DERMATOLOGIST) .So to know the diagnosis, treatment and which moisturizing lotion to use do visit an allopathic dermatologist near you. It will help. Because without examining it is difficult to say what rash you have and what is the solution. Do read the link before you choose your dermatologist ...... http://www.skinmatra.com/single-post/2016/07/03/Skin-Troubles-Here-is-WHAT-NOT-TO-DO