Is fluid surrounding skin expander normal?

I had a double mastectomy after BC with implants fitted in same op. One implant failed because of excessive fluid build up and was removed.(It was aspirated many times but just immediately filled up again.) After 11 months I have had a skin expander fitted (1 week ago) The drain was removed after 2 days but now I'm home the breast has filled with fluid and is the same size as my other one. So an increase of about 50%. Should I be concerned or will it disperse if left alone.