My face is very swollen. Allergic to antibiotic? Benadryl is not working. What else can I do?

I had liposuction 4 days ago on my upper and lower abs. My face and eyes are very swollen today (no issues with breathing). I also have a rash on my face. The only med I have taken in the last 24 hrs is cephalexin. I took Benadryl and stopped antibiotic 4 hrs ago but face and eyes still really swollen. Is this a reaction to the antibiotic? Benadryl is not working. It is my son's b-day and I need to get rid of this rash on my face and for the swelling to go down.