Hi there and welcome,
The first few days to week it will hurt. The key to remember after surgery is to ice it and keep your ankle up. It will hurt WAY more as soon as you put it down to crutch, esp the first few days. So plan on keeping it up wherever you are. If you are still at school, it will help to have an extra chair to put it on during class. I found that even if the leg is just straight out on a chair when you are sitting at say, the dinner table or a desk, etc. then the pain won't be as bad.
You will probably go home the same day. Peroneal tendon tear repair is a pretty standard same day surgery. Meaning not necessarly a standard surgery, but rather, standard to go home the same day. My peroneal tendon had many of the same issues yours does. The biggest pain, really, was the incision, which will be quite long going around your outside ankle bone. Sometimes it would rub in the cast.
If you have any more questions, let me know. Good luck on surgery day.