Post Mole Removal: Purple/Black Spot Inside Red Healed Wound

Sounds like you are still healing.  One thing to have your doctor check is a piece of the stitch is left behind.  The outer layer of stitches are often dark.  There may be a little blood accumulated in the area as well.  It is less likely that a piece of the mole was left behind.  The best thing to do is see the doctor who removed the mole so you can get your question answered.

This sounds to me like it is most likely a dissolving suture that is close enough to the surface of the skin to be visible. When excising facial moles, I frequently do a "layer closure" using a deeper layer of dissolving sutures and a superficial layer of non-dissolving sutures that are removed one week later. The dissolving sutures usually take many weeks or even a few months to dissolve. If they are close to the surface, the purple color can be visible. No need to worry but if it persists and you remain concerned you should return to have the area examined by your surgeon.