Welcome and thanks for posting your to HCM. You have not told any episode of waxing and waning of the problem or time of complete or partial relief from the problem in last few years.
As per your query the most appropriate diagnosis appears to be - Miliaria
crystallina or rubra. The former is the condition of skin experienced by blockage of sweat glands leading to small, clear, and very superficial vesicles without any redness
. When there is more of blockage then it leads to further blockage and inflammation of sweat glands leading to reddish papules(pimple like structure) over back, chest and also the areas described by you. No creams helps us out as such. The best mode is sun protection, wearing cotton clothes, prevention of heat and high humidity, daily two times bath and lastly cold
compression. Eat a lot of vitamin C
containing fruits (all sour fruit). Calamine
lotion can be applied and antihistaminic drugs an be taken for temporary relief form itching It is totally curable and temporary condition provided you keep yourself away from the offending factors.
hope to have provided the best possible information,
With best of hair wishes,
Dr. Sanjay K Kanodia