How noticeable are surgery scars from chron's disease or ulceractive colitis?

Depends: There are 2 approaches to complications from uc or crohn's disease - either open or laparoscopic surgery. The approach depends on the urgency, nature of what is to be done and skill of the surgeon. Many elective surgeries can be done laparoscopically, such as partial or subtotal colectomy, segmental resection. If it is an emergency, i.e. Toxic megacolon, obstruction, then open may be required.