Swelling / lump occurs following flying - both short and long haul flights. I guess it is reaction the reduced cabin pressure (rather than some reaction to in-cabin exhaust chemicals).
1st occurance after 11hr flight, on jawline, just visible maybe 1cm sq, disappeared spontaneously maybe 1 month later.
2nd occurance after 1.5hr flight, between chin / lower lip, slightly larger, more visible as more raised, reduced and disappeared around 3 weeks later.
Both times not painful to touch, and kind of appeared shortly after landing sometime.
Is this some kind of lymphatic thing? Have no idea....I'm reluctant to fly anywhere now....besides the typical leg/ankle-swelling during flight.