Sending prayers and positive thoughts for a speedy and full recovery.
I wouldn't worry too much about the wound not being covered as long as you keep him in a clean environment and from chewing the stitches. I have never faced an LP surgery, but my vets both dog and horse rarely cover surgical stitches - they heal faster when kept clean and dry and exposed to air.
Please never heistate to ask questions - learning and sharing is what YT is all about!