I had appendectomy my scar came open what do i do?

Call your surgeon: It may be infected. Get in to see your surgeon as soon as possible. Most likely it will not require further surgery, only wound care.

See Your Surgeon: Wound openings and wound infections are not uncommon with appendectomies. Wounds opening up may do so because of many reasons primarily due to infection, non-healing, or more serious issues. Please see your surgeon promptly for evaluation.