Hello. It sounds like from your description that your child has contracted a viral illness, likely a mild stomach infection causing the fever and vomiting. Skin rashes often accompany viral illnesses in children, and can be intensely itchy causing much discomfort. I recommend giving your child an over-the-counter antihistamine allergy medicine to relieve the itchiness. For short term effect and help with sleeping, you can give a dose of Benadryl (diphenhydramine). For a non-sedating prolonged effect during the day, try using Zyrtec (cetirizine). You can also apply an anti-itch skin remedy such as calamine lotion. as the viral illness subsides and resolves, the rashes themselves will also feed away and disappear.