How do I prove mistakes from surgeries for appendectomy caused further damage?

If you want to recover for medical malpractice based on errors made in an appendectomy, you will need to prove that the mistakes from surgeries for appendectomy caused you further damage above and beyond what your ruptured or burst appendix would have caused you had those mistakes not been made. This is required because one of the requirements for a plaintiff to bring a malpractice claim is that the specific injuries he or she is seeking damage for would not have happened if the doctor hadn't been negligent. It will be the plaintiff's burden to prove this, so all a doctor would have to do is convince a jury that the damage you are trying to hold him liable for would have actually happened because of the underlying condition, no matter how careful or not careful he was. 

Because it can be really hard to tell what would have happened if a mistake hadn't happened, and because the cause of medical problems can sometimes be difficult to discern, it is imperative that you provide as much evidence as possible to support your argument that the mistake was the but for cause of harm. This evidence is usually going to come in the form of expert witnesses. The more medical experts you have- and the more impressive their credentials- the better the chances of a jury seeing the damage you suffered as a result of the doctor's error. 

To get help finding the right witnesses and gathering the evidence necessary to prove your claim, you need to consult with a medical malpractice lawyer as soon as you can after the botched appendectomy.