Impossible to answer - for one thing, the brown spots may be permanent damage to the leaves which are currently present; the spots may be caused by bacteria, fungus or insect damage; if the spray you used is a fungicide, and the cause of the spots is bacterial, it won't do anything. If the cause is insect infestation and you used a fungicide, that won't do anything. Fungal infections causing leaf spots may respond to the correct fungicidal treatment, meaning you won't have any more spotting occurring than is present already.
All that said, Hydrangea leaf spot is usually treated by removing affected leaves, and improving the growing conditions - it tends to attack plants which are already stressed through drought, lack of nutrients, that sort of thing.