Yes you would definitely see an improvement in someone's Acne if you gave them injections of magnesium over several days. The problem is magnesium is not stored like calcium is stored. It must be constantly supplied in the diet. The way to do this is to eat magnesium rich foods. If you are having a magnesium crisis, as is the case with Acne and diabetes, then you need to get rid of the magnesium antagonists in the diet, such as dairy (calcium). At the point that you have Acne the body is selectively desensitizing itself to foods that antagonize magnesium supplies, resulting in acne. The body simply will not tolerate or digest milk proteins, or gluten proteins, or any other protein that requires magnesium to activate enzymes for the digestion of these proteins.