Phimostop is a medical device specifically designed to treat phimosis. It has no side effects and causes no pain. If you have any discomfort, it is because perhaps the tuboid (made of soft medical silicone) has been placed incorrectly or because you are rushing things too much (we always recommend taking small steps without ever forcing the phimotic ring). If this is the case, please contact us and we will give you full assistance to make the best use of the product.