I'm 17 and have had hormonal acne since I was 12. My skin has cleared up remarkably during the summer, and now I have virtually not a single spot on my face other than a couple of small hyperpigmentation/red marks left over from earlier acne. When I wash my face, it feels flat and smooth. This is the first time since I started combating acne that my skin has improved significantly on its own! I've been following a strict diet for the past few months: I cut out dairy, processed foods, white rice/bread, junk foods, etc. and lived on brown rice, veggies, occasional fish, fruits, and water. This is definitely one of the main factors contributing to the improvement of my skin.
I also realized: my skin seems to have gotten more immune to junk food!! For example, I "cheated" and had cake for breakfast for a whole week during the summer but didn't get a single breakout. I bought a can of Pringles the other day, finished half the can, and woke up the next day without a single new whitehead. I also had frozen pizza twice in the past two weeks and didn't see any changes in my skin! I've also started to eat boxed cereal for breakfast again. I'm thrilled! Does this mean I can slowly start to add foods I love back into my diet? I'm still going to eat lots of veggies, but it would feel good to know I can still enjoy some pizza/snacks once in a while. Any help is appreciated!
There are other possibilities too. You said your acne cleared up during the summer - were you getting more sun exposure? It could be that you were vitamin D deficient. Does your acne usually improve when you get regular sun exposure? Because that's another factor that could be contributing to you clearing up.
Another possibility is that you may have had candida or leaky gut issues, and now you helped your gut repair by doing a strict diet. If your gut is healed, then yes, you can ease up on your diet but within limits because you don't want to mess up your gut flora again.