Is it bad that I used eye drops that are not preservative free for one whole week after PRK eye surgery?

I've been using Systane Ultra Lubricant Eye Drops. After a week and two of those bottles as I used them nearly every 15 minutes and I'm still experiencing blurriness so I reached out to a friend. I showed them what I was using and they mentioned that they should be preservative free. I'm wondering if I did any damaged or caused any harm to my eyes after using eye drops for a whole week that were not preservative free even though I did follow the instructions with all the other drops precisely.