Welcome and thanks for posting your query to HCM.
After reading your query it appears the possibility of "Miliaria" or heat rash
. It occurs due to blockage of ducts of sweat glands. It generally occurs over chest, neck and back areas which are more prone for friction and sweating is high in these areas.
For the betterment kindly follow the suggestions below:
-Wear cotton clothes and cotton undergarments.
-Give cold compression over the affected area.
-Apply over the counter calamine lotion 3-4 times a day.
-Do not scratch or rub the skin as it can lead to further aggravation.
-Kindly stop taking oral steroids as self medication
as it can lead to side effects. So you can take oral anti histamine
or levocetrizine under medial advice.
Despite above measures if the problem is not getting better then it is better to consult a dermatologist
for best guidance. Hope these informations are helpful.
"Wish you good health"
Dr Sanjay Kumar Kanodia
MD (Dermatology & STDs)