Early post op questions after breast implant revision: your surgeon knows best
You would see a change in the shape of the breast or position of the implant if something happened, but your own plastic surgeon is in the best position to advise you about questions like this. It is wise to take good care after double bubble and other revisions so your concern is appropriate.
So how would you know if the implant shifted? You would see it in the mirror when you look at yourself. Follow closely with your surgeon.