Hello,
It can be contact dermatitis, allergic reaction or dermatitis skin. Apply some calamine lotion and take some antihistaminic like Benadryl. Also keep a tab on what you are eating or using so that if there is any offending allergen, then it can be detected and then prevention of that allergen is the best treatment.
I sincerely hope that helps. Take care and regards.
It depends what exactly these look like. Could be anything from shingles to bed bug bites to allergic reaction. See a doctor.