Can you help me to expression the following sentence more naturally in English?

My illusion about her collapsed when I got to know about her. She looke nice at first, but she was really a bad person.

As an intern , my proficieny at medical skills was just average compared with other people, so when I found his white spots in an x-ray, I just examined it and concluded it was not a sign of any diseases or a virus.

overtime, my guilt got decreased and I realized what makes a true doctor and never treat my patient carelessly since then.