First I'd like to say I am so sorry for your having to fight this battle, I know it's not easy.

I'd wager an educated guess that anorexia compromised your body's digestive and endocrine systems and coming back into balance, may take a little time. Just like getting food back in your stomach probably caused some discomfort at first, your skin, also an excretory organ, will have to relearn what to do with food.

Be wary of whey protein if you were on any kind of gaining shake as there is a direct link between whey and acne . I hope you are eating lots of vegetables, high in magnesium, limiting processed foods and sugars , and taking a balanced multivitamin. 45O mg per day of Magnesium and full DVA other vitamins and minerals. When you are healthy your period Will follow . I also lost my period due to anorexia (loss of appetite from depression not body dysmorphia) and it came back with vitamins and proper nutrition. Make sure your bowel movements are healthy and regular and are happening 2 to 3 times a day

Lastly you must be on an emotional roller coaster. Anorexia put your adrenals on hyperdrive. The more emotionally calm you are the more your body/skin will behave, so ask your doctor what measures you can take safely to treat any anxiety or depression issues you're continuing to have. St. John's wort or SAM-e or GABA or all three might help, if you are not already on antidepressants. If you are in antidepressants it is very possible they are a contributing source of your acne

I wish I could give more specific answer - perhaps ED recovery forums would be a good resource.