Small bumps and itchy skin after skin preparation may be due to contact dermatitis, which can be relieved by daily care and medication. 1. Daily care: skin preparation before surgery is to remove and clean the local hair, may be the patient’s allergic reaction to some items in contact with, and then appear red, swollen or itchy, it is recommended to ask the patient’s allergy history, try to choose hypoallergenic items. 2. Medication: If small bumps and itching appear on the skin after surgical skin preparation, if it lasts for a long time, you can use topical medications such as Dinaid cream, mometasone furoate cream, salbutamol ointment, and glycerol lotion for anti-allergy and anti-itch treatment under the advice and guidance of the doctor. If the symptoms continue to be unrelieved, it is recommended to go to a dermatologist, and the medication should be used according to the doctor’s instructions.