Why can't I move my arms above my head for six weeks after breast lift?

So I had a breast lift to correct my tuberous breasts. The doctor said that I was not able to lift my arms above my head for six weeks. She said to do this so my areolas wouldn't stretch. However, they still stretched. I'm going to get a scar revision and get an areola reduction. My question is that really necessary for me to move my arms for that long? I did not get implants with my breast lift. Also if I get an areola reduction, will my areolas stretch again?