Hello,
Annular lesions on the hand particularly the dorsum include a ringworm or Tinea Manum infection, Urticaria(itchy and last less than 24 hours) or due to allergies. Use the anti itch cream and take some antihistaminic like Benadryl for the itching. If the symptoms persist then to rule out ringworm, get a KOH examination of the skin scrapings done from a dermatologist.
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.
Possibly a 'drug rash' relating to medicines taken in the recent past.