11 days post lower face/neck lift, I swole up under my chin like a bullfrog. Is this amount of fluid retention normal?

I would recommend contacting your surgeon so that you can be evaluated in person 11 days after your lower face/neck lift.  It would be unusual to have increased swelling under your chin 11 days after the procedure.  It is possible there could be a fluid collection causing the swelling and the fluid may need to be removed.  

Dear Hollystoy,Thank you for your question. I am sorry to hear that you have had swelling under the chin. At 11 days after Facelift and Necklift, this would not be considered to be normal. I would be seen and evaluated by your Plastic Surgeon.Please let us know if you have any other questions or concerns!Sincerely,Dr. P Daniel Ward

Swelling is normal but without pictures its hard to tell. It looks like you are very recent from surgery so its best to follow up regularly with your doctor for any post surgical concerns.