Acne is just as complex as parasites! I've been taking Ivermectin now for 18 months and my Acne is still the same as it's ever been. Acne depends on a number of factors including:
Parasites
Liver Health
Immune System
Hereditary (whether your mother took Rx) food sensitivity / allergies
Stress Levels
Hormones
Health of your Intestines
But glad that you found something to clear your acne nonetheless!!