hello .thanks for your query..
You may have something knows as Urticaria
.It is common skin condition with frequent exacerbations and remissions.
In most cases,a direct cause is not identified.Treatment is a combination of correct anti histaminic tablets for a few months to help in reducing the severity and frequency of these hives
Start application of a soothing anti pruritic calamine
lotion to relieve the itch.In certain cases, a few bood tests are advised to rule out ant internal causation of the same. I would advise you to visit a dermatologist
to rule out systemic causes of the same.
You should also observe your lifestyle ,diet etc; anything eating/doing if causing the rash
should be identified and eliminated.
Do not worry,although symptoms and treatment course of urticaria is prolonged,these do not pose any danger in most people!
hope this helps!take care...