How should I manage adult acne?

During my school days, I suddenly started getting a lot of acne all over my face and I was very worried.

But even after becoming an adult, I still get adult acne occasionally. It stresses me out a bit;; It comes up in red spots under my chin, and I'm confused as to whether it's because of shaving.

I'm curious about how those of you who have struggled with adult acne manage their condition. I think cleansing methods and dietary habits are important for managing adult acne, so I'm curious if you use any products.

I want to know how to manage adult acne because it keeps appearing and disappearing and it seems like scars are forming.