There isn't sufficient information to give a specific diagnosis as the rash need to be seen and more details on the history of the symptoms are required. It is possible that you're having an allergic reaction, so kindly be observant and keep an eye on exposure to what item is this occurring. Kindly visit a dermatologist so that you can be examined and undergo investigations such as a skin prick test, blood test to find the underlying cause and have it treated accordingly.