Yes, you are allowed to have scars. I have them, and I am 61 years old. I was subject to much of the same thing you were in my Catholic school. It sure was a bit confusing to hear how much God loved you on one hand, while on the other hand the people who represented that God were humiliating you and being abusive to you. What kind of a message was that sending? It affected every area of my life.
However, to me, scars are healed wounds. They may be a reminder of the original wound, but they are healed. What I had for a long time was not scars, but still open, festering, unhealed wounds. A wound has to heal from within and it takes a long time for that to happen, and the base of that wound has to be clean and free from infection. Spiritual wounds require spiritual cleansing, and if you carefully read the Scriptures, you will see that the best cleanser is forgiveness. Forgiveness does NOT mean excusing and condoning wrong actions. It does not mean acting as if these things never happened. It means freeing yourself from the bitterness and hatred and self-pity that keep those wounds open and festering, and keeps you miserable. Others may cause you misery, but the lack of forgiveness will keep you miserable and resentful and bitter, and that is one’s own choice to remain that way.
Forgiveness is so important, that one’s salvation depends upon it. If God was not a forgiving God, we would all be toast. We’d all get what we really deserve. Jesus hung on that Cross and begged His Father to forgive those who had tortured and beat Him and crucified Him. He was, in effect, asking His Father to forgive all of OUR sins, which is really what put Him on that Cross in the first place. We pray the Lord’s prayer and ask God to forgive us our trespasses AS we forgive others. That’s pretty tough language. It’s telling us we must forgive if we want to be forgiven. Forgiveness is not an option, it is a requirement.
I don’t know you, so I cannot judge the degree to which you have forgiven, I can’t judge the state of your soul in this matter. But I can tell you that if you are harboring resentment and bitterness toward certain people and their actions in your life, perhaps you have wounds that haven’t healed yet and need some attention. Only you can judge that. But if you have scars, remember they are healed wounds, and when you mentally look at them they are also reminders of how NOT to treat people so that you don’t inflict the same wounds on others. They can serve a good purpose. These are some of the things I’ve learned and am still learning in this matter.