Hi thanks for your question.The small raised bumps whcih your mentioning could be due to constant itching.
Itcung could be due to some allergens present in your environment or you might be consuming some food to which you are allargic
Other common cause of itching include scabies
,which is infection and involves whole body.
I would suggest you to consult some physician to differentiate between allergic reaction
further management will depenf on diagnosis.
Hope this answer your question.