Just listen to your body, if it hurts don’t do it. Simple..
Start with the treadmill, bike, maybe cross trainer without using the arms. However, I believe if there are complications it will be entirely your fault for not following the aftercare rules. So damned if you do, damned if you don’t 🙁
As long as you don’t start having takeaways and cakes every day…- you shouldn’t put too much weight on. I didn’t exercise for 3 months, I only put on 2 pounds.. To be honest it’s hard to get back to my original weights, but I’m getting there:)