One of my laparoscopy incisions opened 12 days post operation....surgeon says it will grow back together, should i be worried?

Wound healing: After surgery is variable. Depends on overall health, diabetes or not, obesity or not, cigarette smoking or not, etc. As long as there is no sign of wound infection, then you would watch the healing &it will close on its own. Would not re-suture a wound at this stage for concern of causing an infection. Wash with soap &water gently and light bandaid with neosporin of alright with your surgeon.