Thank you for your question. There are various causes of itchy bumpy rashes and these include eczema, bite reaction and scabies.
Heat and sweat can aggravate eczema and make the skin more itchy. Excessive scratching can also make the rash worse.
However, if the rashes are still persistent, it will be good to see your doctor or dermatologist again to re-evaluate the rash to endure a proper diagnosis and treatment.