Lexi will be ok!!
Not to many spay/neuter surgeries go bad. Just make sure she does not 'chew' or 'lick' her stitches after surgery and I would put an Elizabethen collar on her when you are not able to monitor her, preferably her size which would probably be the smallest, xs.
You can buy these at the vet, although they are more expensive. I bought mine off ebay and it was $6, where at the vet they wanted $20. Just do a search for "elizabethen collar" on ebay.
It seems like so many people here have some of snorting/gagging type issues with their yorkies..........Mei Mei also has this problem!! And my mom's dog, Gucci, also has a problem.
She does it more when she is excited or after drinking and it only seems to be one or two little 'gags' and then she stops. I hope it is not a tracheal issue! She is only 6 months old!