I think it depends on your expectations. Are you looking for remorse? Is it Curiosity? Are you just having fun?
If you want to explore the possibility of reconciliation, then maybe share it to get a sense of where he is at. Telling him about the surgery seems like something you would do with a close friend or partner.
Right now, it sounds like you guys are flirting and that's harmless unless you feel yourself getting invested again.
If, however, you don't want to open that door. Then don't.
Seems like it depends on what you want. And, what you're prepared to accept in return.
Just my .02.
Heather
"You know, it's times like these when I realize what a superhero I am." Tony Stark/Iron Man
“Focus on what you can do, then do it with all your heart.” Lois Wilson