While Botox treatments are very safe this type of treatment, like any other, comes with potential risks. The area in which you receive the treatment, is very important in knowing what the potential risks may be. Treatment with Botox around the eyes does carry the potential risk of affecting the movement of the eyes. I recommend that you find a nearby ophthalmologist to perform a complete eye exam particularly assessing the movements and alignment of the eyes. While your Botox treatment may or may not be to blame, a new onset of double vision is always concerning and deserves a full assessment.
Headaches and double vision are really the domain of the neuro-opthalmologist. I would consult this type of specialist to evaluate the cause of your symptoms. Please let me know what the doctor advises.