Every time that I’ve had a cast removed, my skin has had a bad smell to it for a couple of days. The doc says that it is because there is dead skin that will slough off soon and to wait it out.
I usually have scrubbed the skin gently with a mild moisturizing soap and a washcloth and let it air out for a couple of days. If the smell bothers you too much, try cutting up onions, garlic or lemons, as suggested earlier.