This sounds like a heat rash called Miliaria. Please Google' Miliaria" and see if your rash is similar. You will find much information about heat rashes on Google.
The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal
advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.