Hi, I probably wouldn’t use the Cerave SA Smoothing cream as a general moisturiser as it’s quite thick. But it’s great for any dry, rough or bumpy patches. If the acnecide does cause any irritation or dryness it will help sort that out.
Personally I suspect the leg spots are more likely to be caused by a sweat rash/folliculitis or keratosis pilaris than be acne per se. Could even be fungal acne given location.