Right after I had one session of Ultherapy 4 days ago, I've got water bags under my eyes. Can this some how go away?

Any energy based treatment done around the cheeks/lower lids can cause edema in the area.  It will go away but can take several days.

Ulthera is an intensive deep tissue treatment and swelling, particularly in areas where skin and underlying tissues are thin, like the eyelids is common.  This should resolve over several days to two weeks.

There can be some swelling after Ultherapy which should resolve in a few weeks. A combination approach would give the most improvement with Ultherapy. I recommend Ultherapy with RF treatments, lasers, microneedling/PRP or sculptra to get increased collagen, tightening and improve skin tone.  I recommend getting a formal evaluation with an expert. Best, Dr. Emer