Do not try to break it. I think it is cherry eye. It is not very common in cats but chances are still there. It is of pink color. Take it to vet soon. This is a serious problem and it will soon make your pet's eye completely dry. This is tear control gland that swells up and creates this problem. It will heal soon when your vet will reposition this gland. Otherwise you will have to remove it through surgery. So it is better that you consult a vet as soon as possible.