What could have caused my upper lip to swell after Botox between my eyebrows?

If there was no injury to your lip, chances are you had some kind of an allergic reaction to a product other than Botox. This may have been either new lipstick or food that you have come in contact with. Good luck from New York City

 Thank you for your question. Based on your history it is highly unlikely that the lip swelling you encountered had anything to do with the Botox you received to your glabella eight days prior. It was more likely due to an allergic reaction to something else.