There's a subtle change with Jadzia after "INVASIVE PROCEDURES", and you see it as early as 3 episodes after it.
Up to "INVASIVE PROCEDURES", she was more somewhat withdrawn and less open when in conversations with other characters and in actions. After that, she seemed to be more open and free with her expression and demeanor... for example, take her conversation with Pel in "RULES OF ACQUISITION". She was very relaxed, laid back... more open. (I'd even say her conversations with Melora on the runabout in "MELORA", the episode right before, also point to this change in her demeanor.) Then, a bit later in the season in "PLAYING GOD", we see her doing stuff that made her more fun... giving O'Brien the flute (despite it being from Bashir, she probably was in on the joke or even suggested it), wrestling in the morning, eating Klingon food, etc. She was living.
I think the experience of having the Dax symbiote taken out changed her, because she said she felt so alone and empty after it was gone. Once Dax was rejoined with Jadzia, I think she took a hard look at herself and thought, "I'm going to truly live now... I've got all these memories and experiences, I should also be adding to Dax as well." Which makes sense... some people after having a near death experience change and start doing things that they never did before because they held themselves back for whatever reason.
From that point on (for the most part), she was more carefree, fun, and more importantly... alive.