Hello,
It can be due to contact dermatitis or allergic reaction. Check the allergens which you may have come in contact with and take some antihistaminic like Benadryl or Claritin. Also consult a dermatologist as you may need topical as well as oral steroids and get scabies ruled out.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
More like a plant induced or perfume induced dermatitis(Berloque). Calamine lotion applied should help. Do consult doc.