Lexi will be fine Mike. My Diva was spayed last September and also had an umbilical hernia removed at the same time, the scar took longer to heal because of the hernia but she got the all-clear from the vet a few weeks after the op and now 4 months down the line you can not see any evidence that she ever had one!
Lexi should be a bit groggy when you get her home tonight but she should be back to her bouncy self tomorrow; thats when the hard part starts coz you have to restrict their exercise for about 10 days and they dont feel sick so they can get very hyper

Good luck and let us know how Lexi is.