So, just as ejaculating doesn't decrease the levels, ingesting it nor rubbing it in to the skin will help to raise your levels.
In ancient Rome, cum baths were pretty common among women of the elite classes, if one is to believe the depiction of this in Caligula - good film, by the way; at least I thought so. Male slaves would ejaculate into small bowls and the female handmaidens would rub it into the skin of their Ladies.
It was thought that semen would help soften the skin and keep it younger looking.
There may have been some truth to that, because semen has an awful lot of Zinc (3% of the U.S. RDA), an antioxidant which is believed to slow down the aging process of skin.
And, goodness knows, there have been enough studies about the nutritional values. There are over 200 separate proteins, Vitamin C, Calcium, Chlorine, Citirc Acid, Fructose, Lactic Acid, Magnesium, Nitrogen, Phosphorus, Potassium, Sodium, B12, and the aforementioned Zinc. Though, it must be noted, the amounts are not sufficient as to provide any real health benefits.
While women and gay/bi men ingest on a regular basis, I think most men have at least tasted their own cum, so it's not exactly uncommon.
So, go ahead, ingest it if you want.