Bacterial infection 4 months post lipo?

With significant infection there can be diffuse inflammation in the body in an area in a state of recovery might be somewhat more uncomfortable. Nevertheless you should check in with your surgeon.

That would be extremely unusual for an infection to occur 4 months post lipo even after a bacterial UTI.  Liposuction does not consist of placing foreign bodies, so at 4 months all remaining tissue should be alive and healthy.  The only caveat would be the possibility of an infected fluid collection (seroma).  Follow up with your plastic surgeon, and discuss your concerns.Take care and good luck.