Managing allergy shot reactions depends on the type and severity of the symptoms. For mild localized reactions, such as redness, swelling, or itching at the injection site, applying a cold compress can provide relief. Avoid scratching or rubbing the area to prevent further irritation. These reactions typically subside within a few hours to a day and are not usually a cause for concern. Staying hydrated and following post-injection care instructions from your healthcare provider can also help.