The history elicited by you goes in favour of insect bite hypersensitivity
. See whether your work place or your home is nested by insects which bite you. Wear clothes which cover almost your complete body, especially during sleep hours.
Next time if the lesions appear again, then immediately approach a dermatologist
. Because early lesions will give better diagosis and better outcome.
Dr. Ajit Singh kulhari
MD - Skin & VD