Hi,
If you have a personal history of allergies, this is more likely. The rash usually resolves after the irritant or allergen is removed. Cold packs, Benadryl and other antihistamine medications may help relieve the symptoms. However, if it persists, have this evaluated by your dermatologist for proper management and to rule out other causes.
Take care and keep us posted.
Also, try to avoid scratching to prevent secondary bacterial infection.