flying with a seroma

Hi All, 

I'm a new recruit to the breast cancer club. Had a lumpectomy and axillary node clearance on the 16 of April and have been struggling with a seroma under my arm for the last 3 weeks. had 220ml drained off last time (my third draining). I am due to go on a 4 hour flight on the 4th of June and although all the docs have kind of said that's fine none of them seem to confirm that it will not make the seroma worse. its been so terrible and is currently much improved after the drain on Monday but I'm terrified of it coming back big again as it so painful. Has anyone flown with a largish seroma and if so did it make any difference to it before. also if you had a small or drained one did it come back after or during the flight?? any experience would be greatly appreciated.