I must admit to being a bit confused with the saints. I fully understand sacrificing food (fasting) or nice clothing, or humbly keeping quiet when you would rather blast someone. I don’t understand the saints who deliberately mutilated their bodies, like St. Rose of Lima, or the children of Fatima. They are saints and I am not, so I have to assume they know something I don’t. If self-mutilation is wrong, wouldn’t it also be wrong even if done for reparation of sin?
First, keep in mind that self-mutilation and self-mortification are entirely different things. Self-mutilation is the action of deliberately causing physical damage to one’s body because of a disordered desire to injure oneself. It can be symptomatic of mental illness and those who suffer from it should seek medical and/or psychological help. Self-mortification, on the other hand, is the rightly-ordered action of the will to master the demands of the body through carefully-supervised physical disciplines. Those who are just starting out with self-mortification or who are acting on their own should start with small self-denials such as those you mentioned. Only those who feel called to more severe disciplines and who are working with a spiritual director whom they know to be orthodox and balanced should attempt self-mortification on the scale that the saints mortified themselves.
Just as an athlete does not run an Olympic marathon without having trained (and been coached) for many years, so a spiritual athlete requires training and coaching to undertake extreme self-mortification; and just as not everyone is called to be a marathon runner, so such extreme self-mortification is not necessarily something to which every Christian is called.