If you have small itchy bumps on the upper arms that appeared recently and have not improved, it could be helpful to apply a hydrocortisone cream to reduce redness and itchiness. You can find hydrocortisone cream in pharmacies and apply it twice a day. If the bumps are spread over a large area and the itching is severe, you may also consider taking an antihistamine like BENADRYL Allergies as needed. Remember to follow the instructions on the packaging and seek medical advice if the symptoms persist or worsen.