Botox injections around or under the eyes can actually be used to treat lazy eye. In rare cases, Botox that has migrated can cause the eyelid to droop. This side effect usually wears off in a couple of weeks, or can be treated immediately with more Botox to lift the eyelid.
Botox works by weakening the muscles. If you weaken the upper forehead muscles, your brow will drop. This can cause the eyelids to look droopy, which is why most clients prefer to lift the brows rather than lower them.
No, it wouldn't affect the procedure. But if you do have allergies, it could affect the procedure if you are prone to itchy watery eyes.
Results vary from patient to patient and metabolism does play a large role. We find that patient can require multiple syringes spaced over several weeks to achieve desired results. The patient can offend fall in the love with their results while still swollen or and before filler settles.