Skin eruptions, which happens overnight. NOT BED BUGS. Almost anywhere on the body except the face, hands, fore arms, feet. See profile picture.

Could be. apart from infestations allergy to bed covers espcially wool is common.
Dermatology. You should see a dermatologist and obtain a slin biopsy and you will need a strong cortisone type prescription. Picture online is quite small- get an expert opinion.