Opening on Incision Line 3 Months Post-op?

Buried sutures which are intended to dissolve sometimes works her way through the skin before breakdown is complete. This can cause a very small wound. Bring this to the attention of your surgeon.

Based on your description, a suture may have worked its way up and created an wound...  As long as it is not infected, it should heal with local wound care.   You should keep the wound clean (wash daily) and apply Neosporin (if you are not allergic to it) and cover the wound untill you see your plastic surgeon.