Dermatology clinics that specialize in acne treatment

My teenage son's skin has been seriously damaged by acne.

I received treatment for about two months last year at a dermatology clinic near my house, and it got a little better, but my child's eating habits didn't change much. He mostly liked ramen, ham, and instant food, so it was difficult.

But during puberty, hormones are running high, so I have more acne under my chin than last year, and it's red and pus-filled, and it's hard to describe in words. I already have scars on my face.

So I've been to three dermatologists in Yeosu so far, but I haven't seen any good results yet.

What are some good ways to treat acne and where can I find a good dermatologist?