Botox to the Glabella Caused Under Eye Bags, Is This Normal? What Can I Do?

It sounds that your doctor is very appropriate in the treatment plan. The units were not too high. I can't imagine how the Botox would have affected your lower eyelids unless you had the crows feet injected 8 days ago along with the forehead, but you made no mention of that. Possibly, if you had a numbing cream applied prior to the treatment the day before the glabella, you are seeing a dermatologic swelling reaction from that? Gravity often pulls fluids from swelling or dermatitis of the forehead down to the lower eyelids.  There might be some coincidental occurrence of sinusitis, etc.

This is not a typical response to Botox when used in the manner you have described.. Sometimes we can become more aware of areas we have had work on and noticefor the first time things that have always been there. Early development of eyebags can be transcient in the initial stages. You should consult your injecting physician for evaluation.

Botox itself takes several days to take effect.  Even 16 units is a very small dose.  However, there is sufficient variation in how doctors place this agent that I have learn not to say something is impossible.  If this swelling persists over the weekend, I would recommend going back to be assessed by your injecting physician.