What is this red raised lump?

Hello, not sure. Could be several things depending on what was done during your procedure. Your best bet is to make a follow up appointment with your surgeon for evaluation of the area. Good Luck. 

Without pre-op photos- it's difficult to comment accurately. Also, would be helpful to see an operative report. Certain techniques- for example- the open technique--allow for the placement of sutures inside but under the skin. This may be one possible explanation for this problem. Without a physical exam both internally and externally- it's difficult to say. Follow up with your Board Certified PS.

Best to check with your plastic surgeon for an examination.  Could be from the surgery and may be a cyst.