Hello,
I have had cosmetic Botox as well and the drooping of the eye is quite common, but will resolve in a few weeks.
The most common side effect is a mild headache lasting a few hours while severe headaches are rare and always temporary. Slight bruising at the injection site may occur.
Hopefully, the Botox was injected by a board certified plastic surgeon. He or she should have made you aware of the possible complications.
Eyelid droop, known as ptosis, is temporary condition occurs in about 5% of patients. It usually appears 7 to 14 days after the injection and can last 4 to 6 weeks. A more speedy method of treating ptosis is the application of prescription eye drops (iopidine). In many cases, these drops will help resolve the droop within a few days. To reduce the risk of ptosis.
It is also important for a patient to remain vertical for 4-6 hours after the injection. This allows the Botox to be taken up in the treated area and reduces the chance of displacement to other muscles. It is also helpful to contract the treated muscles repeatedly (smile or squint depending on the area treated). Do not touch the injected sites for two to three hours.
The second time I went for Botox in the same area, the drooping did not occur.
I work with plastic surgeons in the OR, let me know if you have any other questions.