Is it dangerous to mix Lidocaine and Metoprolol?

I feel it  is best to do surgery in  a fully accredited surgical facility, especially if you have concerns. You may have to pay a little extra for it, but it is money well-spent. Extremely minor touch ups may be safely performed in an office setting, and on your typical medication. I would voice your concerns with your physician, and I am sure they will consider your safety as the first priority. 

It may not be the Lidocaine that is the concern, but the epinephrine that is mixed with the lidocaine. If your blood pressure is not always under good control with your medication, then the epinephrine might increase the blood pressure and heart rate. Your internist should provide medical clearance to your surgeon prior to undergoing the liposuction. The epinephrine should not be removed from the local anesthetic as it provides for less bleeding and, very importantly, provides for the safety by slow absorption of the anesthetic, and a longer duration of effectiveness. Without the epinephrine, too much local could be absorbed too quickly creating dangerous toxi levels of lidocaine in the blood.

Just like any other procedure, you would need to have medical clearance before this procedure.  Assuming that nothing changed between your original operation and now, you will likely be okay.  However, this is really a question for your doctors who know you best.   Good luck.