Twins suffering from cystic acne that marked their faces were able to heal their skin completely without drugs and without expensive products. How? Changing your diet.
This is what happened to the twins Nina and Randa Nelson , two Californian girls who from puberty onwards had to deal with a form of cystic acne that covered their entire face and had a profound psychological impact on their lives.

After trying Roaccutane without success and having to abandon it due to the side effects, the girls, with a passion for dance, had to overcome a bad depression, for which they could not get out of the house anymore.

But it was enough to change the diet and see the skin improve significantly within a few weeks.
Until the total remission of cystic acne. The before and after photos are truly impressive.
How?

ACNE CYSTIC: THE ENEMY ARE FATS ACCORDING TO DOCTOR MC DOUGALL

Nina and Randa followed Dr. Mc Dougall’s dietary protocol, that is, they managed to eliminate the problem with a very low-fat vegan diet, eating carbohydrates to their fill. The Mc Dougall diet is a vegan diet, but you can also consume two or three servings a week of white meat and white fish, as long as they are fat-free. Referred to as the Starch Solution Diet, the Mc Dougall Diet is a diet that encourages the use of carbohydrates while minimizing fat for weight loss and boosting the immune system.
According to Mc Dougall, fats of any kind (even monounsaturated or polyunsaturated) are to be banned for those suffering from acne and skin problems.
Here in English the scientific references listed by the same doctor.

The two girls even published a book recounting their experience. 
For those with skin problems and cystic acne or other forms of acne, here is an example of the Mc Dougall diet or the Starch Solution diet: those who want to lose weight can stick to the example plan, those who do not have problems with excess pounds but acne-prone skin can increase the doses of carbohydrates (rice, wholemeal bread, pasta). Go to Mc Dougall Method here.