What should I do if I do something stupid and humiliating, and I feel uncomfortable when I think about it, but I can't forget it when I think about it often?

You said yourself that it is naive for time to dilute everything. Who hasn't done anything shameful? Think about it, if you do it, it will be more childish! Only you care about this kind of thing! I've lost enough face. Why should I short someone else's psychology? If you can't face it frankly, others' impression of you will never change. It's no use thinking too much about yourself. Maybe others will laugh at a joke.