Blew my nose lightly after tympanoplasty, did i ruin it?

It's possible: If your hearing hasn't changed, then you're probably ok. To be sure, you might want to have your doctor examine the eardrum. This is a good time to remind everyone to follow your doctor's post-operative instructions! they are given for a reason, not just to make your life difficult!

Hopefully not: It depends on how hard you blew.... For now avoid any further nose blowing as you can dislodge the graft. Use a saline spray if you must rinse the nose. Discuss with your surgeon at your post op check.