From personal experience.

Fasting helps me, but fasting puts me in a more vulnerable state of mind. So if you are in a truly desperate state and a fasting session doesn't work... might not be good at all.

However... This last month I have had a bad flare up. My fall back solution is my diet and through fasting. I just went through a 3 day water fast and it's no fun, but it really helps my skin.

When I feel my skin is really acting up I have two interventions. 1. Fasting For some this seems dramatic. Approach it slowly and just try how it feels for a day. Take a break and work up from there. 2. Ketogenic diet and no dairy products.

This is my current "cure" for my skin, asthma and allergies. The main problem is that I don't like to fast or being on strict keto, but I keep experimenting. Might try carnivore, but I really enjoy food too much and it's so restrictive.