At the end of the surgery, the nursing staff will put a compression vest on you. This serves to minimise swelling and bleeding, and also helps the skin conform to the new chest contour.
Most patients are comfortable because of the action of the local anaesthetic that has been injected into the area during the surgery. If there is any discomfort, this is well controlled with tablet painkillers.
Bruising, swelling and minor lumpiness are all expected and tend to settle quickly. In the first few weeks, it is very common for one side to look different to the other. This will settle over a number of weeks.