We really hope that will never happen! All our products are clean, dermatologist reviewed and/or tested, hypoallergenic, formulated for all skin types and with ingredients that are non-comedogenic. On the same token, we understand not all products will ever work for every single person, so should an allergic reaction occur, we recommend that you stop using the product and get in touch with us via our contact form to let us know. We'll need some additional details in order to review further and provide any recommendations.