You could be having a reaction to the ingredients in your Herbal Salve. You would have to stop taking it to see if that indeed is what maybe causing it or talk to the person who has put you on it. I don't know to much about Herbal Salve..I know more about supplements, You could try taking a good quality fish oil and see if that may help with the itching. Fish oil are also known to be anti-inflammatory supplement.
Here are the ingredients. ActiveIngredient: lisdexamfetaminedimesylate
Inactive Ingredients: microcrystalline cellulose, croscarmellose sodium, and magnesium stearate. The capsule shells (imprinted with S489) contain gelatin, titaniumdioxide,andoneormoreofthefollowing:FD&C Red #3, FD&C Yellow #6, FD&C Blue #1, Black Iron Oxide, and Yellow Iron Oxide.
So tend to doubt that V is causing the itching